KAVANAUGH, Circuit Judge:

Some emissions of air pollutants affect air quality in the States where the pollutants are emitted. Some emissions of air pollutants travel across State boundaries and affect air quality in downwind States. To deal with that complex regulatory challenge, Congress did not authorize EPA to simply adopt limits on emissions as EPA deemed reasonable. Rather, Congress set up a federalism-based system of air pollution control. Under this cooperative federalism approach, both the Federal Government and the States play significant roles. The Federal Government sets air quality standards for pollutants. The States have the primary responsibility for determining how to meet those standards and regulating sources within their borders.

In addition, and of primary relevance here, upwind States must prevent sources within their borders from emitting federally determined "amounts" of pollution that travel across State lines and "contribute significantly" to a downwind State's "nonattainment" of federal air quality standards. That requirement is sometimes called the "good neighbor" provision.

In August 2011, to implement the statutory good neighbor requirement, EPA promulgated the rule at issue in this case, the Transport Rule, also known as the Cross-State Air Pollution Rule. The Transport Rule defines emissions reduction responsibilities for 28 upwind States based on those States' contributions to downwind States' air quality problems. The Rule limits emissions from upwind States' coal- and natural gas-fired power plants, among other sources. Those power plants generate the majority of electricity used in the United States, but they also emit pollutants that affect air quality. The Transport Rule targets two of those pollutants, sulfur dioxide (SO2) and nitrogen oxides (NOx).

Various States, local governments, industry groups, and labor organizations have petitioned for review of the Transport Rule. Although the facts here are complicated, the legal principles that govern this case are straightforward: Absent a claim of constitutional authority (and there is none here), executive agencies may exercise only the authority conferred by statute, and agencies may not transgress statutory limits on that authority.

Here, EPA's Transport Rule exceeds the agency's statutory authority in two independent respects. First, the statutory text grants EPA authority to require upwind States to reduce only their own significant contributions to a downwind State's nonattainment. But under the Transport Rule, upwind States may be required to reduce emissions by more than their own significant contributions to a downwind State's nonattainment. EPA has used the good neighbor provision to impose massive emissions reduction requirements on upwind States without regard to the limits imposed by the statutory text. Whatever its merits as a policy matter, EPA's Transport Rule violates the statute. Second, the Clean Air Act affords States the initial opportunity to implement reductions required by EPA under the good neighbor provision. But here, when EPA quantified States' good neighbor obligations, it did not allow the States the initial opportunity to implement the required reductions with respect to sources within their borders. Instead, EPA quantified States' good neighbor obligations and simultaneously set forth EPA-designed Federal Implementation Plans, or FIPs, to implement those obligations at the State level. By doing so, EPA departed from its consistent prior approach to implementing the good neighbor provision and violated the Act.

For each of those two independent reasons, EPA's Transport Rule violates federal law. Therefore, the Rule must be vacated.

In so ruling, we note that this Court has affirmed numerous EPA clean air decisions in recent years when those agency decisions met relevant statutory requirements and complied with statutory constraints. See, e.g., National Environmental Development Association's Clean Air Project v. EPA, 686 F.3d 803 (D.C.Cir. 2012); API v. EPA, 684 F.3d 1342 (D.C.Cir.2012); ATK Launch Systems, Inc. v. EPA, 669 F.3d 330 (D.C.Cir.2012); NRDC v. EPA, 661 F.3d 662 (D.C.Cir. 2011); Medical Waste Institute & Energy Recovery Council v. EPA, 645 F.3d 420 (D.C.Cir.2011); American Trucking Ass'ns v. EPA, 600 F.3d 624 (D.C.Cir. 2010). In this case, however, we conclude that EPA has transgressed statutory boundaries. Congress could well decide to alter the statute to permit or require EPA's preferred approach to the good neighbor issue. Unless and until Congress does so, we must apply and enforce the statute as it's now written. Our decision today should not be interpreted as a comment on the wisdom or policy merits of EPA's Transport Rule. It is not our job to set environmental policy. Our limited but important role is to independently ensure that the agency stays within the boundaries Congress has set. EPA did not do so here.1

I

A

Under the Clean Air Act, the Federal Government sets air quality standards, but States retain the primary responsibility (if the States want it) for choosing how to attain those standards within their borders. See Train v. NRDC, 421 U.S. 60, 63-67, 95 S.Ct. 1470, 43 L.Ed.2d 731 (1975); Virginia v. EPA, 108 F.3d 1397, 1406-10 (D.C.Cir.1997). The Act thus leaves it to the individual States to determine, in the first instance, the particular restrictions that will be imposed on particular emitters within their borders. (If a State refuses to participate, the Federal Government regulates the sources directly.)

To spell this out in more detail: The Clean Air Act charges EPA with setting National Ambient Air Quality Standards, or NAAQS, which prescribe the maximum permissible levels of common pollutants in the ambient air. See 42 U.S.C. § 7409(a)-(b). EPA must choose levels which, "allowing an adequate margin of safety, are requisite to protect the public health." 42 U.S.C. § 7409(b)(1).

After a lengthy process, the details of which are not relevant here, EPA designates "nonattainment" areas — that is, areas within each State where the level of the pollutant exceeds the NAAQS. See 42 U.S.C. § 7407(d).

Once EPA sets a NAAQS and designates nonattainment areas within the States, the lead role shifts to the States. The States implement the NAAQS within their borders through State Implementation Plans, or SIPs. (As the experienced reader knows, there is no shortage of acronyms in EPA-land.) In their SIPs, States choose which individual sources within the State must reduce emissions, and by how much. For example, a State may decide to impose different emissions limits on individual coal-burning power plants, natural gas-burning power plants, and other sources of air pollution, such as factories, refineries, incinerators, and agricultural activities.

States must submit SIPs to EPA within three years of each new or revised NAAQS. See 42 U.S.C. § 7410(a)(1). Section 110(a)(2) of the Act lists the required elements of a SIP submission.

Section 110(a)(2)(D)(i)(I), the "good neighbor" provision at issue in this case, is one of the required elements of a SIP. The good neighbor provision requires that SIPs:

42 U.S.C. § 7410(a)(2)(D).

The good neighbor provision recognizes that emissions "from `upwind' regions may pollute `downwind' regions." Appalachian Power Co. v. EPA, 249 F.3d 1032, 1037 (D.C.Cir.2001). To put it colloquially, the good neighbor provision requires upwind States to bear responsibility for their fair share of the mess in downwind States. By placing the good neighbor requirement in Section 110(a)(2), Congress established the upwind State's SIP as the vehicle for implementing the upwind State's good neighbor obligation. Of course, an upwind State will not know what it needs to do to meet its good neighbor obligation until it learns the level of air pollution in downwind States, and further learns how much it is contributing to the problems in the downwind States. EPA plays the critical role in gathering information about air quality in the downwind States, calculating each upwind State's good neighbor obligation, and transmitting that information to the upwind State. With that information, the upwind State can then determine how to meet its good neighbor obligation in a new SIP or SIP revision. See 42 U.S.C. § 7410(k)(5).

After EPA quantifies a State's good neighbor obligation, if a State does not timely submit an adequate SIP (or an adequate SIP revision) to take account of the good neighbor obligation as defined by EPA, responsibility shifts back to the Federal Government. Within two years of disapproving a State's SIP submission or SIP revision, or determining that a State has failed to submit a SIP, EPA must promulgate a Federal Implementation Plan to implement the NAAQS within that State. See 42 U.S.C. § 7410(c)(1).

B

The good neighbor provision — and EPA's attempts to implement it — are familiar to this Court from past cases.

In Michigan v. EPA, 213 F.3d 663 (D.C.Cir.2000), we considered a challenge to EPA's 1998 NOx Rule, commonly referred to as the NOx SIP Call, which quantified the good neighbor obligations of 22 States with respect to the 1997 ozone NAAQS. See 63 Fed. Reg. 57,356, 57,358 (Oct. 27, 1998).

The 1998 NOx Rule did not define "amounts which will ... contribute significantly to nonattainment" solely on the basis of downwind air quality impact, as one might have expected given the statutory text. Rather, EPA also considered how much NOx could be eliminated by sources in each State if those sources installed "highly cost-effective" emissions controls. See Michigan, 213 F.3d at 675. On review, some States argued that the statutory text required EPA to order reductions based on air quality impact alone, not cost of reduction. But the Michigan Court found no "clear congressional intent to preclude consideration of cost." Id. at 677 (citation omitted). The Court thus held that EPA may "consider differences in cutback costs, so that, after reduction of all that could be cost-effectively eliminated, any remaining `contribution' would not be considered `significant.'" Id. at 677; see also id. at 677-79. In other words, EPA could use cost considerations to lower an upwind State's obligations under the good neighbor provision.2

In North Carolina v. EPA, 531 F.3d 896 (D.C.Cir.2008), we considered a challenge to EPA's 2005 Clean Air Interstate Rule, or CAIR. See 70 Fed. Reg. 25,162 (May 12, 2005). CAIR built on the 1998 NOx Rule and defined 28 States' good neighbor obligations with respect to the 1997 ozone NAAQS and the 1997 NAAQS for annual levels of fine particulate matter, or annual PM2.5. See id.

CAIR employed two different formulas — both of which incorporated cost considerations — to quantify each State's obligations for the pollutants covered by CAIR, SO2 and NOx. The North Carolina decision held that the formulas went beyond Michigan's authorization to use cost and that the formulas therefore exceeded EPA's statutory authority. EPA may use cost to "require termination of only a subset of each state's contribution," the Court explained, but "EPA can't just pick a cost for a region, and deem `significant' any emissions that sources can eliminate more cheaply." 531 F.3d at 918 (citation, emphasis, and some internal quotation marks omitted). The Court also held that "section 110(a)(2)(D)(i)(I) gives EPA no authority to force an upwind state to share the burden of reducing other upwind states' emissions. Each state must eliminate its own significant contribution to downwind pollution." Id. at 921. The Court emphasized that EPA "may not require some states to exceed the mark." Id.

North Carolina thus articulated an important caveat to Michigan's approval of cost considerations. The statute permits EPA to use cost to lower an upwind State's obligation under the good neighbor provision. See Michigan, 213 F.3d at 675, 677. But EPA may not use cost to increase an upwind State's obligation under the good neighbor provision — that is, to force an upwind State to "exceed the mark." North Carolina, 531 F.3d at 921. Put simply, the statute requires every upwind State to clean up at most its own share of the air pollution in a downwind State — not other States' shares.

C

The North Carolina Court remanded CAIR without vacatur, leaving CAIR in place "until it is replaced by a rule consistent with our opinion." North Carolina v. EPA, 550 F.3d 1176, 1178 (D.C.Cir.2008) (on rehearing).

The Transport Rule is EPA's attempt to develop a rule that is consistent with our opinion in North Carolina. EPA proposed the Transport Rule in August 2010 and finalized it in August 2011. See 75 Fed. Reg. 45,210 (Aug. 2, 2010) (proposed); 76 Fed. Reg. 48,208 (Aug. 8, 2011) (final). The Transport Rule addresses States' good neighbor obligations with respect to three NAAQS: the 1997 annual PM2.5 NAAQS, the 1997 ozone NAAQS, and the 2006 24-hour PM2.5 NAAQS. See id. at 48,209.3

The Transport Rule contains two basic components. First, the Rule defines each State's emissions reduction obligations under the good neighbor provision. Second, the Rule prescribes Federal Implementation Plans to implement those obligations at the State level. We describe each component here in some detail.

EPA began by quantifying the "amounts" of pollution that each State must prohibit under the good neighbor provision — that is, "amounts which will ... contribute significantly to nonattainment" or "interfere with maintenance" of the three NAAQS in other States. 42 U.S.C. § 7410(a)(2)(D)(i).4

EPA used a two-stage approach to quantify each State's obligations under the good neighbor provision.

In the first stage, EPA determined whether a State emits "amounts which will... contribute significantly" to a downwind State's nonattainment of any of the three NAAQS. EPA identified the significantly contributing upwind States based on "linkages" between each upwind State and specific downwind "nonattainment" or "maintenance" areas — that is, downwind areas that EPA modeling predicted would not attain, or absent regulation would not maintain, the NAAQS. Transport Rule, 76 Fed. Reg. at 48,236. An upwind State was linked to a downwind nonattainment or maintenance area for a given NAAQS if EPA modeling showed that the upwind State's contribution to that downwind area exceeded a numerical "air quality threshold" — that is, a specific amount of air pollution sent from the upwind State into the downwind State's air. Id. EPA set the air quality threshold for each pollutant at an amount equal to 1% of the relevant NAAQS. The resulting thresholds were (i) 0.8 ppb for ozone, (ii) 0.15 μg/m3 for annual PM2.5, and (iii) 0.35 μg/m3 for 24-hour PM2.5. Id. If modeling showed that an upwind State would send more than those amounts into a downwind State's air, as measured at a receptor site in a downwind State, the upwind State was deemed a "significant contributor" to the downwind State's air pollution problem.

Those numerical air quality thresholds determined which upwind States had to reduce their SO2 and NOx emissions and which upwind States did not — that is, the thresholds determined which upwind States' emissions "contribute significantly" to downwind States' air pollution problems. Upwind States "whose contributions are below these thresholds," EPA found, "do not significantly contribute to nonattainment or interfere with maintenance of the relevant NAAQS" in downwind States. Id. Because their emissions did not "contribute significantly," those States were not required to cut their emissions for purposes of the good neighbor provision.

As one would expect, this "significant contribution" threshold produced some close cases at the margins. For example, Maryland and Texas were covered for annual PM2.5 based on downwind contributions of 0.15 and 0.18 μg/m3, respectively — just barely meeting the 0.15 μg/m3 threshold. See id. at 48,240. And Texas exceeded the annual PM2.5 threshold at just a single downwind receptor, in Madison, Illinois. See id. at 48,241.5 By contrast, Minnesota and Virginia, with maximum downwind contributions of 0.14 and 0.12 μg/m3, respectively, just missed being covered for annual PM2.5. See id. at 48,240.

For annual PM2.5, a total of 18 States6 exceeded the threshold and were therefore deemed "significant contributors." For 24-hour PM2.5, a total of 22 States7 exceeded the threshold. See id. at 48,241-42. Those States were thus included in the Rule's reduction programs for SO2 and annual NOx, pollutants that contribute to PM2.5 formation. See id. at 48,210. For ozone, a total of 26 States8 exceeded the threshold. See id. at 48,245. Those States were thus included in the Rule's reduction program for ozone-season NOx which contributes to ozone formation. See id. at 48,210; see also 76 Fed. Reg. 80,760 (Dec. 27, 2011) (finalizing six States' inclusion in the Transport Rule for ozone-season NOx).

At the second stage, however, EPA abandoned the air quality thresholds — that is, the stage one standard for whether an upwind State's emissions "contribute significantly" to a downwind State's nonattainment of air quality standards. Instead, at stage two, EPA used a cost-based standard: EPA determined how much pollution each upwind State's power plants could eliminate if the upwind State's plants applied all controls available at or below a given cost per ton of pollution reduced. The cost-per-ton levels applied without regard to the size of each State's "significant contribution" at stage one. In other words, how much pollution each upwind State was required to eliminate was not tied to how much the upwind State contributed to downwind States' air pollution problems.

EPA predicted how far emissions would fall if power plants throughout the State were required to install controls available at or below various cost levels. The cost levels, or thresholds, were expressed in terms of cost per ton of pollutant reduced, with the idea being that plants would install all controls that cost less than the designated threshold.9

EPA then added up the emissions from all of the covered States to yield total regionwide emissions figures for each pollutant, at each cost threshold. See Transport Rule, 76 Fed. Reg. at 48,250-53. The higher the cost level selected, the greater the reduction of emissions, but also the greater the costs and burdens imposed on sources within the States.

Next, EPA used computer modeling to estimate the downwind air quality effects of imposing different cost-per-ton levels on the upwind States. Id. at 48,253. EPA modeled the air quality effects of applying a $500/ton cost level for NOx and ascending cost-per-ton levels for SO2. See id. at 48,255; EPA, Analysis to Quantify Significant Contribution Technical Support Document 15 & n.9 (July 2010), J.A. 2177.

Armed with those two sets of modeling data, EPA proceeded to choose which regionwide cost-per-ton threshold to apply for each of the three pollutants — SO2, annual NOx and ozone-season NOx. EPA consulted both its cost-of-reduction modeling and its air quality modeling and identified what it termed "significant cost thresholds" — that is, cost-per-ton levels at which steep drops in upwind emissions or jumps in downwind air quality would occur. Transport Rule, 76 Fed. Reg. at 48,255; see also id. at 48,255-56. EPA then weighed both air quality and cost concerns in a "multi-factor assessment" to choose the final cost-per-ton levels. Id. at 48,256. The "multi-factor assessment" did not employ any hard formula to weigh those factors.

In the end, EPA settled on a single $500/ton threshold for ozone-season and annual NOx. See id. at 48,256-57.

For SO2, instead of using a single cost threshold for all of the SO2 States, EPA divided the upwind States into two groups for the 2014 program year (that is, the emissions cuts required in 2014). EPA modeling showed that applying a $500/ton cost threshold resolved the attainment problems in the downwind areas to which seven upwind States were linked. See id. at 48,257. Those seven upwind States became the Group 2 States, which were subject to a $500/ton threshold for SO2. See id. But $500/ton did not resolve attainment problems in the downwind areas to which 16 other upwind States were linked. Those 16 upwind States became the Group 1 States, which were subject to a stricter $2,300/ton cost threshold for SO2. See id. at 48,259.

EPA determined the amount of SO2, annual NOx or ozone-season NOx that each covered State could eliminate if its power plants installed all cost-effective emissions controls — that is, those controls available at or below the applicable cost-per-ton thresholds. See id. at 48,260. EPA then used those figures to generate 2012, 2013, and 2014 emissions "budgets" for each upwind State, for each pollutant for which that State was covered. See id. at 48,259-63. The budget is the maximum amount of each pollutant that a State's power plants may collectively emit in a given year, beginning in 2012.10

EPA did not stop there and leave it to the States to implement the required reductions through new or revised State Implementation Plans, or SIPs. Cf. 42 U.S.C. § 7410(k)(5). Instead, EPA simultaneously promulgated Federal Implementation Plans, or FIPs.

The FIPs require power plants in covered upwind States to make the SO2 and NOx reductions needed to comply with each upwind State's emissions budget, as defined by EPA. The FIPs also create an interstate trading program to allow covered sources to comply as cost-effectively as possible. See Transport Rule, 76 Fed. Reg. at 48,271.

The FIPs convert each State's emissions budget into "allowances," which are allocated among power plants in the State. Under the FIPs, it is EPA, and not the States, that decides how to distribute the allowances among the power plants in each State. See id. at 48,284-88.11

The Rule retains a limited, secondary role for SIPs. States have the option of submitting SIPs that modify some elements of the FIPs. See id. at 48,327-28. The first program year for which States can submit such SIPs is 2014. See id. States may also seek to replace the FIPs wholesale, as long as the SIP prohibits the amounts of NOx and SO2 emissions that EPA specified. See id. at 48,328. EPA says it would "review such a SIP on a case-by-case basis." Id. But, importantly, the States do not have a post-Rule opportunity to avoid FIPs by submitting a SIP or SIP revision: The FIPs "remain fully in place in each covered state until a state's SIP is submitted and approved by EPA to revise or replace a FIP." Id.

Since it issued the final rule in August 2011, EPA has taken several subsequent regulatory actions related to the Transport Rule. See 76 Fed. Reg. 80,760 (Dec. 27, 2011) (finalizing six States' inclusion in the Rule for ozone-season NOx); 77 Fed. Reg. 10,324 (Feb. 21, 2012) (making technical adjustments to modeling and delaying assurance penalty provisions until 2014); 77 Fed. Reg. 34,830 (June 12, 2012) (revising budgets for 13 States).

D

An array of power companies, coal companies, labor unions, trade associations, States, and local governments petitioned for review of EPA's Transport Rule.

On December 30, 2011, this Court stayed the Rule pending a decision on the merits. See Order, No. 11-1302, slip op. at 2 (D.C.Cir. Dec. 30, 2011). The Court's order instructed EPA to "continue administering the Clean Air Interstate Rule pending the court's resolution of these petitions for review." Id.

In Part II of this opinion, we address whether the Rule exceeds EPA's authority to order upwind States to reduce "amounts which will ... contribute significantly to nonattainment" in downwind States. In Part III, we address whether the statute permits EPA to issue FIPs without giving the States an initial opportunity to implement the required reductions through SIPs or SIP revisions. In Part IV, we consider the remedy.

II

In this Part, we analyze petitioners' argument that EPA exceeded its statutory authority under the "good neighbor" provision. Under the statute, EPA is limited to ordering upwind States to reduce "amounts which will ... contribute significantly to nonattainment" in downwind States. 42 U.S.C. § 7410(a)(2)(D)(i).

A

The Transport Rule defines States' obligations under Section 110(a)(2)(D)(i)(I) of the Clean Air Act, a provision sometimes described as the "good neighbor" provision. See 42 U.S.C. § 7410(a)(2)(D)(i)(I); Michigan v. EPA, 213 F.3d 663, 671 (D.C.Cir.2000). The good neighbor provision requires that a State Implementation Plan, or SIP:

42 U.S.C. § 7410(a)(2)(D). The good neighbor provision recognizes that not all air pollution is locally generated: Some ambient air pollution "is caused or augmented by emissions from other states. Emissions from `upwind' regions may pollute `downwind' regions." Appalachian Power Co. v. EPA, 249 F.3d 1032, 1037 (D.C.Cir.2001).

Although the statute grants EPA significant discretion to implement the good neighbor provision, the statute's text and this Court's decisions in Michigan and North Carolina establish several red lines that cabin EPA's authority. Those red lines are central to our resolution of this case.

First, and most obviously, the text of Section 110(a)(2)(D)(i)(I) tells us that the "amounts which will ... contribute" to a downwind State's nonattainment are at most those amounts that travel beyond an upwind State's borders and end up in a downwind State's nonattainment area.12 The statute is not a blank check for EPA to address interstate pollution on a regional basis without regard to an individual upwind State's actual contribution to downwind air quality.

Moreover, the statutory text and this Court's decision in North Carolina v. EPA demonstrate that EPA may not force a State to eliminate more than its own "significant" contribution to a downwind State's nonattainment area — that is, to "exceed the mark," as we put it in North Carolina. 531 F.3d 896, 921 (D.C.Cir. 2008). Thus, once EPA reasonably designates some level of contribution as "insignificant" under the statute, it may not force any upwind State to reduce more than its own contribution to that downwind State minus the insignificant amount.13

Second, under the terms of the statute and as we explained in North Carolina, the portion of an upwind State's contribution to a downwind State that "contribute[s] significantly" to that downwind State's "nonattainment" necessarily depends on the relative contributions of that upwind State, of other upwind State contributors, and of the downwind State itself. Each upwind State may be required to eliminate only its own "amounts which will ... contribute significantly" to a downwind State's "nonattainment." As explained in North Carolina, EPA may not require any upwind State to "share the burden of reducing other upwind states' emissions." Id. In other words, the statutory text — which refers to "amounts" which will "contribute significantly" to a downwind State's "nonattainment" — contains not just an absolute component (meaning that an upwind State's insignificant amounts are not covered) but also a relative component (meaning that each State's relative contribution to the downwind State's nonattainment must be considered).

Moreover, the end goal of the statute is attainment in the downwind State. EPA's authority to force reductions on upwind States ends at the point where the affected downwind State achieves attainment.

Therefore, if the downwind State would attain the NAAQS but for upwind States' contributions — that is, if the entire above-NAAQS amount is attributable to upwind States' emissions — then the upwind States' combined share is the entire amount by which the downwind State exceeded the NAAQS. And as we said in North Carolina, when EPA allocates that burden among the upwind States, EPA may not force any upwind State to "share the burden of reducing other upwind states' emissions." Id. Each upwind State must bear its own fair share. Therefore, the "significance" of each upwind State's contribution cannot be measured in a vacuum, divorced from the impact of the other upwind States. Rather, the collective burden must be allocated among the upwind States in proportion to the size of their contributions to the downwind State's nonattainment. Otherwise, EPA would violate the statute and our decision in North Carolina.14

A specific example helps illustrate that point. Suppose the NAAQS is 100 units, but the downwind State's nonattainment area contains 150 units. Suppose further that the downwind State contributes 90 units, and three upwind States contribute 20 units each. Because the upwind States are responsible for the downwind State's exceeding the NAAQS by 50 units, the downwind State is entitled to at most 50 units of relief from the upwind States so that the downwind State can achieve attainment of the NAAQS. Distributing those obligations in a manner proportional to their contributions, each of the three upwind States' significant contribution would be, at most, 16 2/3 units. Or suppose instead that the three upwind States contribute 10, 20, and 30 units respectively. Distributing those obligations in a manner proportional to their contributions, those three States' significant contributions would be at most 8 1/3, 16 2/3, and 25 units, respectively, leading to the combined reduction of 50 units needed for the downwind State to reach attainment.15

In addition, our decisions in Michigan and North Carolina establish that EPA may consider cost, but only to further lower an individual State's obligations. See Michigan, 213 F.3d at 675; North Carolina, 531 F.3d at 918. Under Michigan, moreover, EPA may do so in a way that benefits some upwind States more than others. See 213 F.3d at 679. In other words, in order to prevent exorbitant costs from being imposed on certain upwind States, EPA may lower the obligations imposed on those States.

Third, to conform to the text of the statute, EPA must also ensure that the combined obligations of the various upwind States, as aggregated, do not produce more than necessary "over-control" in the downwind States — that is, that the obligations do not go beyond what is necessary for the downwind States to achieve the NAAQS.

Even when EPA carefully conforms to the above limits on its authority, the possibility of over-control in downwind States still arises because multiple upwind States may affect a single downwind State and, conversely, a single upwind State may affect multiple downwind States. The requirement to prevent such over-control comes directly from the text of the statute: The good neighbor provision of the statute targets those emissions from upwind States that "contribute significantly to nonattainment" of the NAAQS. EPA may require only those reductions that are necessary for downwind States to attain the NAAQS. The good neighbor provision is not a free-standing tool for EPA to seek to achieve air quality levels in downwind States that are well below the NAAQS. Therefore, if modeling shows that a given slate of upwind reductions would yield more downwind air quality benefits than necessary for downwind areas to attain the NAAQS, EPA must attempt to ratchet back the upwind States' obligations to the level of reductions necessary and sufficient to produce attainment in the downwind States.16

To be sure, as even petitioners acknowledge, there may be some truly unavoidable over-control in some downwind States that occurs as a byproduct of the necessity of reducing upwind States' emissions enough to meet the NAAQS in other downwind States. See Industry & Labor Reply Br. 11 n.2. For those reasons, EPA must have some discretion about how to reasonably avoid such over-control. Moreover, because multiple upwind States may affect a single downwind State, and because a single upwind State may affect multiple downwind States, it may not be possible to accomplish the ratcheting back in an entirely proportional manner among the upwind States. Our cases recognize as much. See Michigan, 213 F.3d at 679; North Carolina, 531 F.3d at 908. But the point remains: EPA must avoid using the good neighbor provision in a manner that would result in unnecessary over-control in the downwind States. Otherwise, EPA would be exceeding its statutory authority, which is expressly tied to achieving attainment in the downwind States.

B

We now apply those principles to the EPA Transport Rule. "It is axiomatic that an administrative agency's power to promulgate legislative regulations is limited to the authority delegated by Congress." Bowen v. Georgetown Univ. Hosp., 488 U.S. 204, 208, 109 S.Ct. 468, 102 L.Ed.2d 493 (1988); see also Michigan v. EPA, 268 F.3d 1075, 1081 (D.C.Cir.2001) ("EPA is a federal agency — a creature of statute," and may exercise "only those authorities conferred upon it by Congress."). An agency may not exceed a statute's authorization or violate a statute's limits. If a statute is ambiguous, an agency that administers the statute may choose a reasonable interpretation of that ambiguity — but the agency's interpretation must still stay within the boundaries of the statutory text. See Chevron U.S.A. Inc. v. NRDC, 467 U.S. 837, 842-44, 104 S.Ct. 2778, 81 L.Ed.2d 694 (1984).17

In the Transport Rule, EPA used a two-stage approach to define "amounts which will ... contribute significantly" to downwind attainment problems. The first stage identified those upwind States that were "significant contributors" to downwind attainment problems. EPA determined that a State's contribution to a downwind nonattainment or maintenance area was significant if it exceeded a numerical "air quality threshold" of 0.8 ppb for ozone, 0.15 μg/m3 for annual PM2.5, and 0.35 μg/m3 for 24-hour PM2.5. Transport Rule, 76 Fed. Reg. 48,208, 48,236 (Aug. 8, 2011). States "whose contributions are below these thresholds," EPA found, "do not significantly contribute to nonattainment or interfere with maintenance of the relevant NAAQS." Id. Those upwind States were off the hook altogether.

But an upwind State that exceeded the significance threshold at even one downwind State's receptor was drawn wholesale into the Rule's second stage — cost-based emissions reductions. At that second stage, EPA abandoned the previous measure of significance — the numerical air quality thresholds, which were based on the quantity of pollution an upwind State sent to a downwind area. Instead, EPA switched over to relying on cost of reduction alone. EPA required each State's power plants to cut all of the emissions they could eliminate at a given cost per ton of pollution reduced — regardless of the "amounts" of the State's emissions EPA deemed to "contribute significantly" at stage one and regardless of the relative contributions of the other upwind States and the downwind State.

We perceive at least three independent but intertwined legal flaws in EPA's approach to the good neighbor provision. Those flaws correspond to the three requirements we outlined above that come from the statutory text.

First, and most fundamentally, the Transport Rule is flawed because the requirement that EPA imposed on upwind States was not based on the "amounts" from upwind States that "contribute significantly to nonattainment" in downwind States, as required by the statute and our decision in North Carolina.

Petitioners claim that the initial stage of EPA's analysis — the numerical air quality thresholds, which used a bright-line test for whether a State's downwind emissions "contribute significantly" — created a "`floor' below which any contribution is, by definition, viewed as insignificant." Industry & Labor Br. 20. Petitioners argue that EPA has no statutory authority to compel States to reduce amounts of pollution that are "insignificant." Therefore, petitioners contend that EPA could not ignore that floor at the later stage, when it calculated each State's "significant contribution" based on cost.18

We agree with petitioners. The Transport Rule includes or excludes an upwind State based on the amount of that upwind State's significant contribution to a nonattainment area in a downwind State. That much is fine. But under the Rule, a State then may be required to reduce its emissions by an amount greater than the "significant contribution" that brought it into the program in the first place. That much is not fine.

Put more plainly, EPA determined that a State was subject to the good neighbor provision if it contributed at least a certain threshold amount to air pollution in a downwind State. But EPA then imposed restrictions based on region-wide air quality modeling projections; those restrictions could require upwind States to reduce emissions by more than the amount of that contribution.

EPA's approach poses a fundamental legal problem — one that derives from the text of the statute and from our precedents. Our decision in Michigan held that EPA may use cost considerations to require "termination of only a subset of each state's contribution." 213 F.3d at 675. And our decision in North Carolina made clear that EPA may not use cost to force an upwind State to "exceed the mark." 531 F.3d at 921.19

By using a numerical threshold at the initial stage — and thereby creating a floor below which "amounts" of downwind pollution were not significant — EPA defined the "mark," to use the term employed in North Carolina. EPA could not then ignore that mark and redefine each State's "significant contribution" in such a way that an upwind State's required reductions could be more than its own significant contribution to a downwind State.20

EPA now claims that the Rule's air quality thresholds were established for a "limited analytical purpose" and "otherwise say nothing about what part of each State's contribution should be considered `significant.'" EPA Br. 33. That claim rings hollow. EPA itself said in the final rule that "states whose contributions are below these thresholds do not significantly contribute to nonattainment or interfere with maintenance of the relevant NAAQS." Transport Rule, 76 Fed. Reg. at 48,236. EPA therefore acknowledged that amounts below the threshold are not "amounts which will ... contribute significantly" to downwind attainment problems.21

In short, EPA used the air quality thresholds to establish a floor below which "amounts" of air pollution do not "contribute significantly."22 The statute requires a State to prohibit at most those "amounts" which will "contribute significantly" — and no more. If amounts below a numerical threshold do not contribute significantly to a downwind State's nonattainment, EPA may not require an upwind State to do more. The Transport Rule does not adhere to that basic requirement of the statutory text and our precedents.23

Second, EPA's Transport Rule also runs afoul of the statute's proportionality requirement as described in our decision in North Carolina: EPA has "no authority to force an upwind state to share the burden of reducing other upwind states' emissions." 531 F.3d at 921; see Industry & Labor Br. 33 (in imposing SO2 budgets, EPA "did not even consider the relative contributions of the various States"). EPA's "redistributional instinct may be laudatory," North Carolina, 531 F.3d at 921, but it cannot trump the terms of the statute. Under the statute, each upwind State that contributes to a downwind nonattainment area is responsible for no more than its own "amounts which will ... contribute significantly" to the downwind State's pollution problem. To be sure, under Michigan, EPA may rely on cost-effectiveness factors in order to allow some upwind States to do less than their full fair share. See 213 F.3d at 675; cf. Petitioning States' Br. 17, Michigan, 213 F.3d 663 (No. 98-1497). But when EPA asks one upwind State to eliminate more than its statutory fair share, that State is necessarily being forced to clean up another upwind State's share of the mess in the downwind State. Under the statute and North Carolina, that is impermissible.

Here, EPA's Transport Rule violated the statute because it made no attempt to calculate upwind States' required reductions on a proportional basis that took into account contributions of other upwind States to the downwind States' nonattainment problems.

In the same vein, EPA's Transport Rule failed to take into account the downwind State's own fair share of the amount by which it exceeds the NAAQS. See Industry & Labor Br. 24-25. How "significantly" an upwind State contributes to a downwind State's nonattainment also depends in part on how much of the above-NAAQS amount comes from the downwind State itself. As we explained above, EPA therefore must factor in the downwind State's own contribution, alongside those of the various upwind States. But EPA did not do that here.

Third, and relatedly, EPA also failed to ensure that the collective obligations of the various upwind States, when aggregated, did not produce unnecessary over-control in the downwind States. EPA's statutory authority, once again, is limited to attaining the NAAQS in the downwind States. EPA may not require upwind States to do more than necessary for the downwind States to achieve the NAAQS. Here, EPA did not try to take steps to avoid such over-control.24

In sum, EPA's authority derives from the statute and is limited by the statutory text.25 EPA's reading of Section 110(a)(2)(D)(i)(I) — a narrow and limited provision — reaches far beyond what the text will bear.

Although the statutory text alone prohibits EPA's Rule, the statutory context provides additional support for our conclusion. The Supreme Court, in analyzing Section 109 of the Clean Air Act, rejected the premise that Congress would "alter the fundamental details of a regulatory scheme" in "ancillary provisions" — in other words, that Congress would "hide elephants in mouseholes." Whitman v. American Trucking Ass'ns, 531 U.S. 457, 468, 121 S.Ct. 903, 149 L.Ed.2d 1 (2001). The good neighbor provision is one of more than 20 SIP requirements in Section 110(a)(2). It seems inconceivable that Congress buried in Section 110(a)(2)(D)(i)(I) — the good neighbor provision — an open-ended authorization for EPA to effectively force every power plant in the upwind States to install every emissions control technology EPA deems "cost-effective." Such a reading would transform the narrow good neighbor provision into a "broad and unusual authority" that would overtake other core provisions of the Act. Gonzales v. Oregon, 546 U.S. 243, 267, 126 S.Ct. 904, 163 L.Ed.2d 748 (2006). We "are confident that Congress could not have intended to delegate a decision of such economic and political significance to an agency in so cryptic a fashion." FDA v. Brown & Williamson Tobacco Corp., 529 U.S. 120, 160, 120 S.Ct. 1291, 146 L.Ed.2d 121 (2000).

* * *

States are obligated to prohibit only those "amounts" of pollution "which will... contribute significantly" to downwind attainment problems — and no more. Because the Transport Rule exceeds those limits, and indeed does not really try to meet those requirements, it cannot stand.

III

There is a second, entirely independent problem with the Transport Rule. EPA did not stop at simply quantifying each upwind State's good neighbor obligations. Instead, in an unprecedented application of the good neighbor provision, EPA also simultaneously issued Federal Implementation Plans, or FIPs, to implement those obligations on sources in the States. EPA did so without giving the States an initial opportunity to implement the obligations themselves through their State Implementation Plans, or SIPs.

The Clean Air Act ordinarily gives States the initial opportunity to implement a new air quality standard on sources within their borders; States do so by submitting SIPs. See 42 U.S.C. §§ 7407(a), 7410(a)(1). Here, by preemptively issuing FIPs, EPA denied the States that first opportunity to implement the reductions required under their good neighbor obligations. EPA justifies its "FIP-first" approach by pointing to its earlier findings that the States had failed to meet their good neighbor obligations. But those findings came before the Transport Rule quantified the States' good neighbor obligations. EPA's approach punishes the States for failing to meet a standard that EPA had not yet announced and the States did not yet know.

Under the Act, EPA has authority to set standards, but the statute reserves the first-implementer role for the States. That division of labor applies not just to the NAAQS but also to the good neighbor provision, Section 110(a)(2)(D)(i)(I), as EPA itself has recognized several times in the past. When EPA defines States' good neighbor obligations, it must give the States the first opportunity to implement the new requirements.

A

"Under the Clean Air Act, both the Federal Government and the States exercise responsibility for maintaining and improving air quality." American Trucking Ass'ns v. EPA, 600 F.3d 624, 625 (D.C.Cir. 2010). The Act sets forth a basic division of labor: The Federal Government establishes air quality standards, but States have primary responsibility for attaining those standards within their borders. See Train v. NRDC, 421 U.S. 60, 63-67, 95 S.Ct. 1470, 43 L.Ed.2d 731 (1975); American Trucking, 600 F.3d at 625-26; Virginia v. EPA, 108 F.3d 1397, 1406-10 (D.C.Cir.1997); see also 42 U.S.C. § 7401(a) ("The Congress finds ... that air pollution prevention (that is, the reduction or elimination, through any measures, of the amount of pollutants produced or created at the source) and air pollution control at its source is the primary responsibility of States and local governments...."); 42 U.S.C. § 7407(a) ("Each State shall have the primary responsibility for assuring air quality within the entire geographic area comprising such State....").26

That statutory division of authority is strict. This Court has described the Train-Virginia line of cases as erecting a statutory "federalism bar" under Section 110 of the Act. See Appalachian Power Co. v. EPA, 249 F.3d 1032, 1046 (D.C.Cir.2001) (citing Train, 421 U.S. 60, 95 S.Ct. 1470; Virginia, 108 F.3d 1397); Michigan v. EPA, 213 F.3d 663, 687 (D.C.Cir.2000). That statutory federalism bar prohibits EPA from using the SIP process to force States to adopt specific control measures. See Michigan, 213 F.3d at 687; Virginia, 108 F.3d at 1410.

In Train, the Supreme Court invoked that statutory division of labor in holding that the Clean Air Act gives EPA "no authority to question the wisdom of a State's choices of emission limitations," so long as the State's SIP submission would result in "compliance with the national standards for ambient air." 421 U.S. at 79, 95 S.Ct. 1470. The Court stated:

Id. (emphasis added); see also Union Electric Co. v. EPA, 427 U.S. 246, 256, 269, 96 S.Ct. 2518, 49 L.Ed.2d 474 (1976) (EPA may not reject a SIP on grounds of technical or economic infeasibility; that "would permit the Administrator or a federal court to reject a State's legislative choices in regulating air pollution, even though Congress plainly left with the States, so long as the national standards were met, the power to determine which sources would be burdened by regulation and to what extent").

Similarly, in Virginia, this Court held that EPA had no authority under Section 110 to condition its approval of northeastern States' SIPs on the States' adoption of California's vehicle emission control measures. See 108 F.3d at 1401-10. The Court relied on the basic principle that the States, not EPA, are the primary implementers under Section 110. See id. at 1410 ("section 110 does not enable EPA to force particular control measures on the states").

In sum, Title I of the Act establishes a "partnership between EPA and the states." NRDC v. Browner, 57 F.3d 1122, 1123 (D.C.Cir.1995). The terms of that partnership are clear: EPA sets the standards, but the States "bear primary responsibility for attaining, maintaining, and enforcing these standards." American Lung Ass'n v. EPA, 134 F.3d 388, 389 (D.C.Cir.1998).

B

With that basic structure in mind, we consider the question presented here: whether EPA may use its rulemaking authority to quantify States' obligations under Section 110(a)(2)(D)(i)(I) and simultaneously issue Federal Implementation Plans, without giving the States a first opportunity to comply.

We begin by briefly describing the set of statutory provisions on which EPA relies here.

EPA is the first mover in regulating ambient air pollution in Title I of the Clean Air Act. Section 109 requires EPA to promulgate NAAQS for common air pollutants. See Whitman v. American Trucking Ass'ns, 531 U.S. 457, 462, 121 S.Ct. 903, 149 L.Ed.2d 1 (2001) (citing 42 U.S.C. § 7409(a)). But once EPA sets a NAAQS, "responsibility under the Act shifts from the federal government to the states." Lead Industries Ass'n v. EPA, 647 F.2d 1130, 1137 (D.C.Cir.1980).

Section 110 governs State Implementation Plans. Section 110(a)(1) requires States to submit SIPs to implement each new or revised NAAQS. See 42 U.S.C. § 7410(a)(1). Section 110(a)(2) lists many elements that a SIP must contain in order to ensure that the Plan will be comprehensive enough to enable the State to attain the NAAQS. See 42 U.S.C. § 7410(a)(2).27 The good neighbor provision, Section 110(a)(2)(D)(i)(I), is one of those required elements.

Section 110(c)(1) creates a federal backstop if the States fail to submit adequate SIPs. When EPA finds that a State "has failed to make a required submission" or "disapproves a State implementation plan submission in whole or in part" because of a SIP "deficiency," EPA must "promulgate a Federal implementation plan" within two years, "unless the State corrects the deficiency" in the meantime in a manner approved by EPA. 42 U.S.C. § 7410(c)(1). In essence, the issue here is whether a State's implementation of its good neighbor obligation can be considered part of the State's "required submission" in its SIP (or whether the SIP can be deficient for failing to implement the good neighbor obligation) even before EPA quantifies the State's good neighbor obligation. We think not. EPA's quantifying of a State's good neighbor obligation and setting of a State's emissions budget is what "require[s]" the State to make a "submission" implementing that obligation on sources within the State. After EPA has set the relevant emissions budgets for each State, EPA may require States to submit new SIPs under Section 110(a)(1) or to revise their SIPs under Section 110(k)(5). That is the approach EPA has used in the past. In short, once EPA defines or quantifies a State's good neighbor obligation, the State must have a reasonable time to implement that requirement with respect to sources within the State.28

In short, the triggers for a FIP are EPA's finding that the SIP fails to contain a "required submission" or EPA's disapproving a SIP because of a "deficiency." But logically, a SIP cannot be deemed to lack a required submission or be deemed deficient for failing to implement the good neighbor obligation until after EPA has defined the State's good neighbor obligation. Once it defines the obligation, then States may be forced to revise SIPs under Section 110(k)(5) or to submit new SIPs under Section 110(a)(1). Only if that revised or new SIP is properly deemed to lack a required submission or is properly deemed deficient may EPA resort to a FIP for the State's good neighbor obligation.

C

1

In light of Section 110(c)(1), EPA here made "a finding of failure to submit and/or disapproved a SIP submission" for each State with respect to each NAAQS for which that State would be covered. EPA Br. 44 (citing 42 U.S.C. § 7410(c)(1)); see also EPA, Status of CAA 110(a)(2)(D)(i)(I) SIPs Final Rule Technical Support Document (July 2011) (EPA, SIPs TSD), J.A. 3167.29 On the basis of those findings, EPA asserted authority to issue the Transport Rule FIPs.

But EPA's many SIP disapprovals and findings of failure to submit share one problematic feature: EPA made all of those findings before it told the States what emissions reductions their SIPs were supposed to achieve under the good neighbor provision. See EPA, SIPs TSD, J.A. 3167.

EPA sees no problem with that. In EPA's view, there is no difference between a State's obligation to comply with the NAAQS and a State's good neighbor obligation: States must submit SIPs addressing both within three years of a NAAQS, or face FIPs.

But there is a difference — a glaring one — between the two obligations. A NAAQS is a clear numerical target. For example, the NAAQS for annual PM2.5 is 15 μg/m3. Every State knows precisely what numerical goal its SIP must achieve. If a State misses that clear numerical target, it has only itself to blame.

By contrast, the good neighbor obligation is not a clear numerical target — far from it — until EPA defines the target. Even after EPA sets a NAAQS, an upwind State's good neighbor obligation for that pollutant is nebulous and unknown. The statutory standard is "amounts" of pollution which will "contribute significantly to nonattainment" or "interfere with maintenance" of the new NAAQS in a downwind State. There is no way for an upwind State to know its obligation without knowing levels of air pollution in downwind States and then apportioning its responsibility for each downwind State's nonattainment. Therefore, the upwind State's obligation remains impossible for the upwind State to determine until EPA defines it.30 Without further definition by EPA, a prohibition on "amounts which will ... contribute significantly" is like a road sign that tells drivers to drive "carefully." The regulated entities — here, the upwind States — need more precise guidance to know how to conform their conduct to the law. A SIP logically cannot be deemed to lack a "required submission" or deemed to be deficient for failure to meet the good neighbor obligation before EPA quantifies the good neighbor obligation.

EPA faults the States for not hitting that impossible-to-know target with their SIP submissions. In effect, EPA's view is that the only chance States have to hit the target is before EPA defines the target. By the time EPA makes the target clear, it's already too late for the States to comply.

Interestingly, outside of this litigation, EPA has itself recently and repeatedly recognized that it makes no sense for States to act until EPA defines the target. Just a few weeks ago, for example, in a separate proceeding EPA said that while some elements of a SIP submission are "relatively straightforward," "others clearly require interpretation by EPA through rulemaking, or recommendations through guidance, in order to give specific meaning for a particular NAAQS." 77 Fed. Reg. 46,361, 46,363 (Aug. 3, 2012). "For example, section 110(a)(2)(D)(i) requires EPA to be sure that each state's SIP contains adequate provisions to prevent significant contribution to nonattainment of the NAAQS in other states. This provision contains numerous terms that require substantial rulemaking by EPA in order to determine such basic points as what constitutes significant contribution." Id. at n.7. Thus, EPA has said that the good neighbor provision "clearly require[s] interpretation by EPA through rulemaking, or recommendations through guidance, in order to give specific meaning for a particular NAAQS." Id.; see also, e.g., 77 Fed. Reg. 45,320, 45,323 & n.7 (July 31, 2012) (same); 77 Fed. Reg. 43,196, 43,199 & n.7 (July 24, 2012) (same); 77 Fed. Reg. 22,533, 22,536 & n.7 (Apr. 16, 2012) (same); 76 Fed. Reg. 40,248, 40,250 & n.5 (July 8, 2011) (same).

In this litigation, however, EPA insists that the text of Section 110(c)(1) compels its FIP-first approach. But EPA pursues its reading of the statutory text down the rabbit hole to a wonderland where EPA defines the target after the States' chance to comply with the target has already passed. Cf. FCC v. Fox Television Stations, Inc., ___ U.S. ___, 132 S.Ct. 2307, 2317, 183 L.Ed.2d 234 (2012) ("A fundamental principle in our legal system is that laws which regulate persons or entities must give fair notice of conduct that is forbidden or required."); id. ("regulated parties should know what is required of them so they may act accordingly"); Christopher v. SmithKline Beecham Corp., ___ U.S. ___, 132 S.Ct. 2156, 2168, 183 L.Ed.2d 153 (2012) ("It is one thing to expect regulated parties to conform their conduct to an agency's interpretations once the agency announces them; it is quite another to require regulated parties to divine the agency's interpretations in advance....").

We take a different view. Statutory text "cannot be construed in a vacuum. It is a fundamental canon of statutory construction that the words of a statute must be read in their context and with a view to their place in the overall statutory scheme." Roberts v. Sea-Land Services, Inc., ___ U.S. ___, 132 S.Ct. 1350, 1357, 182 L.Ed.2d 341 (2012) (quoting Davis v. Michigan Dep't of Treasury, 489 U.S. 803, 809, 109 S.Ct. 1500, 103 L.Ed.2d 891 (1989)).

Title I's core two-step process is that the Federal Government sets end goals and the States choose the means to attain those goals. See Michigan, 213 F.3d at 687; see also Virginia, 108 F.3d at 1410. EPA's theory — that EPA can define the end goals for the good neighbor provision and simultaneously issue federal plans to implement them — upends that process and places the Federal Government firmly in the driver's seat at both steps. The FIP-first approach is incompatible with the basic text and structure of the Clean Air Act.

In our view, determining the level of reductions required under Section 110(a)(2)(D)(i)(I) is analogous to setting a NAAQS. And determining the level of reductions under the good neighbor provision triggers a period during which States may submit appropriate SIPs under Section 110(a)(1) or SIP revisions under Section 110(k)(5).

That approach fits comfortably within the statutory text and structure. In both situations — setting a NAAQS and defining States' good neighbor obligations — EPA sets the numerical end goal. And in both cases, once the standards are set, "determining the particular mix of controls among individual sources to attain those standards" remains "a State responsibility." 1998 NOx Rule, 63 Fed. Reg. 57,356, 57,369 (Oct. 27, 1998).

2

Other contextual and structural factors also support our conclusion that Section 110(a)(2)(D)(i)(I) preserves the basic principle that States, not the Federal Government, are the primary implementers after EPA has set the upwind States' good neighbor obligations.

Section 110's particular function in the statutory scheme is to give the States the first opportunity to implement the national standards EPA sets under Title I. See 42 U.S.C. § 7410(a)-(c); see also Train, 421 U.S. at 79, 95 S.Ct. 1470; Virginia, 108 F.3d at 1410; Michigan, 213 F.3d at 686-87. The good neighbor requirement's placement in Section 110(a) — a provision calling for State-level regulation — strongly suggests that Congress intended States to implement the obligations set forth in Section 110(a)(2)(D)(i)(I). By contrast, if EPA's FIP-first interpretation were to prevail, Section 110(a)(2)(D)(i)(I) would not fit well in Section 110(a).

Moreover, Title I contains a separate provision, Section 126, that explicitly contemplates direct EPA regulation of specific sources that generate interstate pollution. See 42 U.S.C. § 7426(b)-(c); see also Appalachian Power, 249 F.3d at 1046. Section 126(b) permits a State to petition EPA for a finding that a source in a neighboring State emits pollution in violation of Section 110(a)(2)(D)(i).31 See 42 U.S.C. § 7426(b). Section 126(c) gives EPA discretion to impose severe sanctions, including "emission limitations and compliance schedules," on a source for which a finding has been made. 42 U.S.C. § 7426(c); see also 42 U.S.C. § 7509. The fact that Congress explicitly authorized EPA to use direct federal regulation to address interstate pollution suggests it did not contemplate direct Federal regulation in Section 110(a)(2)(D)(i)(I). Cf. Whitman, 531 U.S. at 467-68, 121 S.Ct. 903; General Motors Corp. v. United States, 496 U.S. 530, 541, 110 S.Ct. 2528, 110 L.Ed.2d 480 (1990). And as this Court has previously held, that Section 126 imposes "extrinsic legal constraints" on State autonomy "does not affect a state's discretion under § 110." Appalachian Power, 249 F.3d at 1047 (emphasis added).

In sum, the text and context of the statute, and the precedents of the Supreme Court and this Court, establish the States' first-implementer role under Section 110. We decline to adopt a reading of Section 110(a)(2)(D)(i)(I) that would blow a hole in that basic structural principle.32

3

The novelty of EPA's approach underscores its flaws. In the past, EPA has applied the good neighbor provision in the States-first way we have outlined here.

The 1998 NOx Rule (which we addressed in Michigan) quantified each State's good neighbor obligation but then gave the States 12 months to submit SIPs to implement the required reductions. See 63 Fed. Reg. at 57,358, 57,450-51; 42 U.S.C. § 7410(k)(5). Indeed, EPA explicitly assured States that the Rule did not intrude on their authority to choose the means to achieve the EPA-defined end goal. See 1998 NOx Rule, 63 Fed. Reg. at 57,369. EPA then explained, persuasively, why it made sense not to deviate from Title I's standard division of labor in the good neighbor context:

Id. at 57,370 (emphases added).

In Michigan, this Court held that the 1998 Rule did not transgress the Train-Virginia federalism bar. But the terms of the Michigan Court's approval highlight how flagrantly the new Transport Rule crosses that line. We said: "EPA does not tell the states how to achieve SIP compliance. Rather, EPA looks to section 110(a)(2)(D) and merely provides the levels to be achieved by state-determined compliance mechanisms." 213 F.3d at 687 (emphasis added). We emphasized that States had a "real choice" how to implement the required reductions. Id. at 688.

Like the 1998 NOx Rule, the 2005 Clean Air Interstate Rule gave States the first crack at implementing the reductions required by EPA. See 70 Fed. Reg. 25,162, 25,263 (May 12, 2005) (requiring SIPs within 18 months). When EPA issued CAIR FIPs in April 2006, about a year after it promulgated CAIR, it clarified that it intended the FIPs to serve as a "Federal backstop" to the ongoing SIP process, and did not intend to "take any other steps to implement FIP requirements that could impact a State's ability to regulate their sources in a different manner" until "a year after the CAIR SIP submission deadline." See CAIR FIPs, 71 Fed. Reg. 25,328, 25,330 (Apr. 28, 2006). That timetable, EPA assured the States, would allow EPA "to approve timely SIPs before implementation of FIP requirements occurs." Id. at 25,331 (emphasis added).

In both the 1998 NOx Rule and the 2005 CAIR, EPA was therefore careful not to infringe the States' first-implementer role. EPA's own past practice and statements illustrate the anomaly of its new FIP-first approach.

D

On a separate tack, EPA does not concede that it denied the States their rightful chance to implement their good neighbor obligations. It contends States did have an opportunity to submit SIPs. In EPA's view, once it issued the 2006 24-hour PM2.5 NAAQS, States had three years under Section 110(a)(1) to seek and obtain EPA approval of SIPs addressing their good neighbor obligations.

But to reiterate, the problem is that the three-year period expired before EPA issued the Transport Rule and defined the good neighbor obligations of upwind States. EPA has an answer for that — one we find extraordinarily unpersuasive. In its view, each State should have come up with (i) its own definition of "amounts which will ... contribute significantly" and (ii) its own modeling and methodology for applying that definition. See EPA Br. 48 ("EPA has never stated that its methodology is the only way") (emphasis omitted).

In effect, EPA claims the statute requires each State to take its own stab in the dark at defining "amounts which will... contribute significantly" to a downwind State's nonattainment. The State would then have to apply that homemade definition using its own homemade methodology.33

Of course, once a State takes its stab, EPA could disapprove it — especially if the State defined its own obligation to be less than what EPA deemed it to be. Experience appears to bear that out: Petitioners point out that every Transport Rule State that submitted a good neighbor SIP for the 2006 24-hour PM2.5 NAAQS was disapproved. See State & Local Br. 29-31; State & Local Reply Br. 5-7.

That should not come as a surprise. In the 1998 NOx Rule, EPA acknowledged that pre-Rule stabs in the dark were bound to fail. "Without determining an acceptable level of NOx reductions," EPA warned, "the upwind State would not have guidance as to what is an acceptable submission." 63 Fed. Reg. at 57,370. And States would incur significant costs developing those SIP submissions.

As EPA repeatedly reminds this Court, interstate pollution is a collective problem that requires a comprehensive solution. See EPA Br. 5 ("Absent effective federal control, individual States often have little economic or political incentive to self-impose regulatory controls (and attendant costs) within their States solely to address air quality problems in other States."). And EPA itself has recognized that having each State independently guess at its own good neighbor obligations is not a plausible solution to interstate pollution: "It is most efficient — indeed necessary — for the Federal government to establish the overall emissions levels for the various States." 1998 NOx Rule, 63 Fed. Reg. at 57,370 (emphasis added).

Yet EPA now encourages us to suspend disbelief and conclude that under the statute, a State's only chance to avoid FIPs is to make a successful stab in the dark — a feat that not one Transport Rule State managed to accomplish. EPA clearly does not believe the stab-in-the-dark approach would really permit States to avoid FIPs — its own past statements show that. But EPA's authority to issue these FIPs rests on our accepting its rickety statutory logic.

We decline the invitation. Our duty is to "interpret the statute as a symmetrical and coherent regulatory scheme and fit, if possible, all parts into an harmonious whole." FDA v. Brown & Williamson Tobacco Corp., 529 U.S. 120, 133, 120 S.Ct. 1291, 146 L.Ed.2d 121 (2000) (citations and internal quotation marks omitted). EPA's FIP-first approach fails that test.

When EPA quantifies States' good neighbor obligations, it must give the States a reasonable first opportunity to implement those obligations. That approach reads Section 110(a)(2)(D)(i)(I) in harmony with the rest of Section 110. It preserves Title I's Federal-State division of labor — a division repeatedly reinforced by the Supreme Court and this Court. And it accords with the commonsense notion that Congress did not design the good neighbor provision to set the States up to fail.34

IV

The decision whether to vacate a flawed rule "depends on the seriousness of the order's deficiencies (and thus the extent of doubt whether the agency chose correctly) and the disruptive consequences of an interim change that may itself be changed." Allied-Signal, Inc. v. NRC, 988 F.2d 146, 150-51 (D.C.Cir.1993) (internal quotation marks omitted); see also Davis County Solid Waste Mgmt. v. EPA, 108 F.3d 1454, 1459 (D.C.Cir.1997).

Here, we have no doubt that the agency chose incorrectly. The Transport Rule stands on an unsound foundation — including EPA's flawed construction of the statutory term "amounts which will ... contribute significantly to nonattainment." 42 U.S.C. § 7410(a)(2)(D)(i). That deficiency is too fundamental to permit us to "pick and choose portions" of the rule to preserve. North Carolina v. EPA, 531 F.3d 896, 929 (D.C.Cir.2008). And as with the Clean Air Interstate Rule, the Transport Rule's "fundamental flaws foreclose EPA from promulgating the same standards on remand." Id. (internal quotation marks omitted). EPA's chosen manner of implementing the Rule — issuing FIPs without giving the States a post-Rule opportunity to submit SIPs — also rests on a misreading of the statute.

We therefore vacate the Transport Rule rulemaking action and FIPs, and remand to EPA.

The remaining question is the status of CAIR. In North Carolina, this Court initially held that CAIR's "fundamental flaws" required vacatur. 531 F.3d at 929. On rehearing, the Court reconsidered its initial decision and modified its order to remand CAIR without vacatur. North Carolina v. EPA, 550 F.3d 1176, 1178 (D.C.Cir.2008). The Court noted that under our precedents, it is appropriate to remand without vacatur "where vacatur would at least temporarily defeat the enhanced protection of the environmental values covered by the EPA rule at issue." Id. (internal quotation marks, brackets, and ellipsis omitted). The Court was "convinced that, notwithstanding the relative flaws of CAIR, allowing CAIR to remain in effect until it is replaced by a rule consistent with our opinion would at least temporarily preserve the environmental values covered by CAIR." Id.

In accordance with our Order granting the motions to stay the Transport Rule, EPA has continued to administer CAIR. See Order, No. 11-1302, at 2 (D.C.Cir. Dec. 30, 2011); see also http://www.epa.gov/cair. Vacating CAIR now would have the same consequences that moved the North Carolina Court to stay its hand — and indeed might be more severe now, in light of the reliance interests accumulated over the intervening four years. We therefore conclude, as did the Court in North Carolina, that the appropriate course is for EPA to continue to administer CAIR pending its development of a valid replacement.35

* * *

We vacate the Transport Rule and the Transport Rule FIPs and remand this proceeding to EPA. EPA must continue administering CAIR pending the promulgation of a valid replacement.

So ordered.

ROGERS, Circuit Judge, dissenting:

To vacate the Transport Rule, the court disregards limits Congress placed on its jurisdiction, the plain text of the Clean Air Act ("CAA"), and this court's settled precedent interpreting the same statutory provisions at issue today. Any one of these obstacles should have given the court pause; none did. The result is an unsettling of the consistent precedent of this court strictly enforcing jurisdictional limits, a redesign of Congress's vision of cooperative federalism between the States and the federal government in implementing the CAA based on the court's own notions of absurdity and logic that are unsupported by a factual record, and a trampling on this court's precedent on which the Environmental Protection Agency ("EPA") was entitled to rely in developing the Transport Rule rather than be blindsided by arguments raised for the first time in this court.

Congress has limited the availability of judicial review of challenges to final rules promulgated by the EPA in two ways that are relevant here. Under CAA section 307(b)(1), 42 U.S.C. § 7607(b)(1), petitions for judicial review must be filed within sixty days of promulgation of a final rule, and under CAA section 307(d)(7)(B), 42 U.S.C. § 7607(d)(7)(B), "[o]nly an objection to a rule or procedure which was raised with reasonable specificity during the period for public comment ... may be raised during judicial review." The court has, until today, strictly enforced these requirements, which exist for two important reasons: to enforce repose so that the rulemaking process is not crippled by surprise challenges to matters that were rightfully presumed settled, and to guarantee an agency's expert consideration and possible correction of any flaws in its rules before the matter reaches a court. Instead the court casts aside both jurisdictional provisions, upending these two fundamental principles. In so doing, the court thus fails to "maintain uniformity of the court's decisions" on these "question[s] of exceptional importance." FED. R.APP. P. 35(a)(1) & (2).

As one basis underlying its vacatur of the Transport Rule, the court permits a collateral attack on prior final rules in which EPA disapproved state implementation plan ("SIP") submissions with respect to the "good neighbor provision," CAA § 110(a)(2)(D)(i)(I), 42 U.S.C. § 7410(a)(2)(D)(i)(I), or found States failed to submit such a SIP at all. In those Final SIP Rules, EPA unambiguously stated its interpretation that States had an independent obligation under section 110(a) to submit "good neighbor" SIPs regardless of whether EPA first quantified each State's emission reduction obligations. Under section 307(b)(1), States had sixty days to seek judicial review of those Final SIP Rules to challenge EPA's interpretation of section 110(a). EPA's authority to promulgate the federal implementation plans ("FIPs"), pursuant to section 110(c), in the Transport Rule was triggered by EPA having published those Final SIP Rules, and under section 307(b)(1) States may not collaterally attack the propriety of those Final SIP Rules now. This is not a mere technicality — EPA developed and promulgated the Transport Rule with the knowledge that all but three States did not seek judicial review of its interpretation of section 110(a) and in light of this court's opinion in North Carolina v. EPA, 531 F.3d 896 (D.C.Cir.2008). The court therefore lacks jurisdiction under section 307(b)(1) to consider States' belated challenge to EPA's interpretation of section 110(a) as part of its review of the Transport Rule; the petitions challenging the Final SIP Rules filed by three States are not consolidated with the petitions challenging the Transport Rule, as they involve separate provisions of the CAA and different final rules. The court glosses over the plain text and structure of section 110 to avoid that reality, and in the process rewrites sections 110(a) and 110(c), altering the triggering mechanism for States' obligations to submit "good neighbor" SIPs and EPA's obligation to promulgate FIPs, based on its own speculative conclusion that the process Congress adopted is "impossible" for States to follow. To reach its conclusion, the court today holds that the CAA requires what it previously held the CAA ambiguously permits EPA to do.

As another ground to vacate the Transport Rule, the court concludes that, under EPA's two-step approach to defining "significant contribution" under the "good neighbor" requirement in section 110(a)(2)(D)(i)(I), a State "may be required to reduce its emissions by an amount greater than the `significant contribution' that brought it into the program in the first place." Op. at 25. No objection was made during the Transport Rule administrative proceedings to EPA's approach, let alone its statutory authority, to use different, unrelated measures of significance for inclusion and budget-setting. Acknowledging this, the court reaches beyond the Transport Rule administrative record, despite section 307(d)(7)(B)'s clear command, to find jurisdiction. But the three reasons it offers do not add up. By suggesting that EPA acted inconsistently with North Carolina in adopting a two-step approach, with different, unrelated measures of "significant contribution" for inclusion and budget-setting, the court ignores that in North Carolina this court expressly declined to disturb that same approach. 531 F.3d at 916-17. In relying on a comment expressing a policy preference made during the administrative proceedings of the predecessor of the Transport Rule (to which petitioners failed to alert the court until rebuttal oral argument), the court ignores that the comment does not challenge EPA's statutory authority to pursue its two-step approach, and the fact that no one petitioned the court in North Carolina for judicial review based on that comment, which is why the court in North Carolina left that approach undisturbed, see id. The court also ignores that the prior rulemaking docket was not incorporated into the Transport Rule administrative proceedings. Together, these "ignored" facts demonstrate that EPA had no reason to suspect any party before it in the Transport Rule administrative proceedings subscribed to the objection stated in the old comment, nor even to locate and consider that comment. Finally, EPA's rejection on technical grounds of alternative approaches for measuring "significant contribution" based solely on air quality, not cost and air quality, during the Transport Rule administrative proceedings says nothing about whether EPA would have refused to entertain petitioners' new objection in this court that EPA was statutorily required to modify its two-step approach by making the inclusion threshold of step-one a floor for reductions under the cost approach of step-two. The alternative approaches EPA considered and rejected are not even the approaches petitioners now endorse, and, in any event, cannot excuse a failure to state their objection with "reasonable specificity" during the Transport Rule administrative proceedings.

The court's remaining reasons for vacatur lack merit. First, the court concludes EPA violated the "good neighbor" provision's "proportionality" requirement, but petitioners presented no such statutory authority argument in their briefs, instead challenging EPA's grouping of States for purposes of SO2 reduction as arbitrary and capricious. Even if they had, the court lacks jurisdiction because the argument is premised on speculation that EPA's two-step approach to measuring "significant contribution" might require States to reduce emissions by more than the amount that triggered their inclusion in the Transport Rule in the first place — the same argument over which the court lacks jurisdiction due to petitioners' failure to challenge EPA's statutory authority for its approach during the Transport Rule administrative proceedings. On the merits, the court's "proportionality" conclusion contradicts the court's opposite conclusion in North Carolina that EPA's measurement of a State's "significant contribution" did not have to correlate directly with its air quality impact "relative to other upwind states." 531 F.3d at 908 (citing Michigan v. EPA, 213 F.3d 663, 679 (D.C.Cir.2000)). Similarly, the court's holding that EPA failed to consider the effect of in-state emissions is likewise premised on the sub-threshold argument. Further, the court's "in-State emissions" and its "over-control" conclusions are contradicted by the Transport Rule administrative record.

I.

Section 307(b)(1) of the CAA, 42 U.S.C. § 7607(b)(1), requires a petition for judicial review of EPA final actions to be filed within sixty days of publication in the Federal Register. "The filing period in the Clean Air Act `is jurisdictional in nature'; if the petitioners have failed to comply with it, we are powerless to address their claim." Med. Waste Inst. & Energy Recovery Council v. EPA, 645 F.3d 420, 427 (D.C.Cir.2011) (quoting Motor & Equip. Mfrs. Ass'n v. Nichols, 142 F.3d 449, 460 (D.C.Cir.1998)).

Slinger Drainage, Inc. v. EPA, 237 F.3d 681, 682 (D.C.Cir.2001) (quoting Stone v. Immigration & Naturalization Serv., 514 U.S. 386, 405, 115 S.Ct. 1537, 131 L.Ed.2d 465 (1995) (internal quotation marks, alterations, and citation omitted)). Accordingly, in Medical Waste this court dismissed a challenge to a final rule for lack of jurisdiction where petitioners failed to seek judicial review when EPA "first use[d]" its statutory approach, 645 F.3d at 427 (emphasis added). "An objection is considered a collateral attack only if `a reasonable [petitioner] ... would have perceived a very substantial risk that the [rule] meant what the [agency] now says it meant.'" S. Co. Servs., Inc. v. FERC, 416 F.3d 39, 45 (D.C.Cir.2005) (internal quotations marks, citation, and alterations omitted).

The Transport Rule, responding to States' failures to submit adequate "good neighbor" SIPs, is a FIP that addresses the interstate transport of emissions in twenty-seven States in the eastern United States for three national ambient air quality standards ("NAAQS"): the 1997 8-hour ozone NAAQS, the 1997 annual PM2.5 NAAQS, and the 2006 24-hour PM2.5 NAAQS.1 See Transport Rule, 76 Fed. Reg. 48,208 (Aug. 8, 2011). In the Transport Rule, EPA determined that the same level of emission reduction obligations would apply for each of these three NAAQS. See id. at 48,264. Over a year prior to promulgating the Transport Rule, EPA promulgated Final SIP Rules publishing findings that twenty-nine States and territories had failed to submit SIPs with the required "good neighbor" provisions for the 2006 24-hour PM2.5 NAAQS.2 See Failure to Submit Good Neighbor SIP Finding, 75 Fed. Reg. 32,673 (June 9, 2010); Tennessee Failure to Submit Good Neighbor SIP Finding, 76 Fed. Reg. 43,180 (July 20, 2011). In these Final SIP Rules, EPA stated:

Id. at 32,674; see also 76 Fed. Reg. at 43,180-81 (Tennessee). The Final SIP Rules further state that the findings of failure to submit were of nationwide scope and effect, and therefore pursuant to section 307(b)(1), 42 U.S.C. § 7607(b)(1), a petition for judicial review had to be filed with the D.C. Circuit within sixty days of the publication of the findings in the Federal Register. See Failure to Submit Good Neighbor SIP Finding, 75 Fed. Reg. at 32,675-76; Failure to Submit Good Neighbor SIP Finding (Tennessee), 76 Fed. Reg. at 43,182-83. No State filed a petition for judicial review.

Other States submitted 2006 24-hour PM2.5 SIPs with "good neighbor" provisions, but EPA disapproved that portion of the SIP submissions of ten States covered by the Transport Rule: Alabama, Georgia, Indiana, Kansas, Kentucky, Missouri, New Jersey, New York, North Carolina, and Ohio.3 In the Final SIP Rules, EPA rejected objections that States had no obligation to submit SIPs until EPA had quantified the States' amount of "significant contribution" and that EPA was required to permit States to revise their SIPs prior to imposing a FIP pursuant to 42 U.S.C. § 7410(c)(1).4 The Final SIP Rules disapproving the "good neighbor" SIP submissions alerted the affected States that "petitions for judicial review must be filed in the United States Court of Appeals for the appropriate circuit by September 19, 2011," see, e.g., 76 Fed. Reg. at 43,136 (Alabama), the sixty day deadline prescribed by CAA section 307(b)(1), 42 U.S.C. § 7607(b)(1). Only Georgia, Kansas, and Ohio filed petitions for judicial review of EPA's disapproval action and their petitions are not consolidated with the petitions now under review, as they challenge different final rules.5

A.

Now that EPA has, as it warned, promulgated FIPs for States covered by the Transport Rule, State petitioners contend that EPA lacked authority to do so for the 2006 24-hour PM2.5 NAAQS because "a FIP can cure a deficiency only in a required submission, and States were not required to include SIP provisions to eliminate `significant contributions' not yet defined by EPA legislative rule." State Petrs' Br. at 31. If a State wished to object that under section 110(a) it had no obligation to include "good neighbor" provisions in its SIP until EPA quantified its "significant contribution" in emission reduction budgets, then the CAA required it do so at the time EPA found it had not met its SIP "good neighbor" obligation. State petitioners offer no response in their reply brief to EPA's position that this argument is a collateral attack barred by section 307(b)(1). See Resp.'s Br. at 46-47.

Ignoring the plain terms of section 307(b)(1) as well as this court's long-settled precedent, the court reaches the merits of this issue despite its lack of jurisdiction. In the Final SIP Rules finding States had failed to submit "good neighbor" SIPs, EPA put covered States on unambiguously "sufficient notice" that it interpreted the CAA as placing an independent obligation on each State to include adequate "good neighbor" provisions in its SIP regardless of whether EPA had prospectively quantified its amount of "significant contribution." S. Co. Servs., 416 F.3d at 44. By the very nature of the Final SIP Rules, EPA was informing States that they had not met their obligation to submit "good neighbor" SIPs, an obligation States now contend they never had. Furthermore, EPA warned that its findings of failure to submit triggered the two-year FIP clock of section 110(c)(1), and not the SIP Call provision of section 110(k)(5). See Failure to Submit Good Neighbor SIP Finding, 75 Fed. Reg. at 32,673-74; Failure to Submit Good Neighbor SIP Finding (Tennessee), 76 Fed. Reg. at 43,180-81. In alerting States to the judicial review deadline, EPA reiterated that States had sixty days to file "any petitions for review ... related to [] findings of failure to submit SIPs related to the requirements of [the `good neighbor' provision]." Failure to Submit Good Neighbor SIP Finding, 75 Fed. Reg. at 32,676; Failure to Submit Good Neighbor SIP Finding (Tennessee), 76 Fed. Reg. at 43,183 (emphases added). Not having sought judicial review of the Final SIP Rules determining that they failed to submit required "good neighbor" SIPs, States may not now object that they were not required to submit "good neighbor" SIPs until EPA first quantified their reduction obligations. "The sixty day window provided by statute has long since closed, and we may not reopen it and entertain a belated challenge ... now." Med. Waste, 645 F.3d at 427. Therefore, the court lacks jurisdiction over the collateral attacks by petitioners Louisiana, Michigan, Nebraska, Oklahoma, Virginia, and Wisconsin, as part of the Transport Rule petitions, on EPA's interpretation of section 110(a) stated in the Final SIP Rules finding they failed to submit required "good neighbor" SIPs.

Similarly on notice, neither Alabama nor Indiana petitioned for judicial review of EPA's disapproval of their SIP submissions. In the Final SIP Rule disapproving Alabama's SIP submission, EPA quotes one commenter as stating:

76 Fed. Reg. at 43,131. EPA responded that "the state obligation stems from the CAA itself.... States had an opportunity to conduct their own analyses regarding interstate transport." Id. (emphasis added). EPA also warned that it was obligated to promulgate a FIP within two years of disapproving Alabama's SIP, see id. at 43,132, and rejected comments that the SIP Call revision process of section 110(k)(5) should apply, because, in its view, that provision applies only where there is an existing, approved SIP, see id. at 43,133. In its summary of Indiana's comments on the proposed disapproval of its SIP submission, EPA noted that Indiana took the position that EPA "should provide [the State] the opportunity to revise its [] SIP once the Transport Rule is completed" and that a "FIP is [] contrary to the spirit of the CAA by unnecessarily limiting [S]tate authority." 76 Fed. Reg. at 43,177. EPA responded, relying on the CAA's plain text, that Indiana was required by section 110(a) to submit SIPs with adequate "good neighbor" provisions, and that upon disapproving its submission, EPA had a legal obligation under the CAA to promulgate a FIP. See id. Alabama and Indiana's comments, along with EPA's responses, demonstrate that the two States were on clear notice of EPA's interpretation of the CAA as imposing an independent obligation on the States to submit "good neighbor" SIPs, even in the absence of EPA-quantified amounts of "significant contribution." Yet neither Alabama nor Indiana sought judicial review of EPA's Final SIP Rules disapproving their SIP submissions, and their attempt now to collaterally attack those Final SIP Rules is barred. See Med. Waste, 645 F.3d at 427.

Given EPA's clear statements in its Final SIP Rules disapproving States' SIP submissions and finding they failed to submit required "good neighbor" SIPs, there is no basis to conclude that State petitioners might not have perceived a substantial risk that EPA meant what it said. See S. Co. Servs., 416 F.3d at 45. The instant case, involving consolidated petitions challenging the Transport Rule, is therefore not the appropriate forum to decide whether, under section 110(a), States have an independent obligation to submit "good neighbor" SIPs when EPA has not first quantified amounts of "significant contribution." EPA promulgated Final SIP Rules in which it made its interpretation clear; judicial challenge to those rules is the proper forum to decide the question.6

Indeed, the court itself forecasts this conclusion: "EPA's many SIP disapprovals and findings of failure to submit share one problematic feature: EPA made all of those findings before it told the States what emission reductions their SIPs were supposed to achieve under the "good neighbor" provision." Op. at 31-32 (emphasis in original). However "problematic" the court views this "feature" of those Final SIP Rules, this is a "problem" this three-judge panel is powerless to resolve because it lacks jurisdiction under CAA section 307(b)(1) to entertain State petitioners' "back-door challenge" to EPA's interpretation of section 110(a) stated in those Final SIP Rules. Natural Res. Def. Council v. EPA, 824 F.2d 1146, 1150 (D.C.Cir.1987) (internal quotation marks omitted).

The court responds that the dissent "conflates" State petitioners' collateral attack on the Final SIP Rules announcing their Section 110(a) SIP obligations with State petitioners' supposedly distinct argument that EPA cannot promulgate a FIP simultaneously with its quantification of a State's emission reduction obligations. See Op. at 12 n.1, 37 n.34. This response misleadingly quotes the statute, and in the process, proves the dissent's point. The court states "the statute says that EPA must issue a FIP within two years after a State fails to make a `required submission' or submits a deficient SIP. But a State cannot be `required' to implement its "good neighbor" obligation in a SIP `submission'... until it knows the target set by EPA." Id. at 37 n.34.7 That is not what the statute says. Section 110(c) provides that:

42 U.S.C. § 7410(c)(1) (emphases added). EPA's FIP obligation is therefore not triggered, without more, by a State's mere failure to submit a SIP required by section 110(a), but instead by an explicit EPA Final Rule finding that the State either failed to submit a required SIP or an adequate SIP. A challenge to EPA's interpretation of section 110(a) must therefore be brought as a petition for judicial review of those Final SIP Rules announcing that States failed to meet their section 110(a) "good neighbor" SIP obligations. See Med. Waste, 645 F.3d at 427. Under the plain terms of the CAA, EPA's obligation (and authority) to promulgate a FIP is triggered by those Final SIP Rules, and the process by which EPA must promulgate a FIP is governed by section 110(c), not, as the court posits, by section 110(a). The court therefore, and not the dissent, does the conflating by turning what should be a challenge to EPA's FIP authority under section 110(c) into a collateral attack on EPA's interpretation of section 110(a) set forth in the prior Final SIP Rules.

The plain text of section 110(c)(1) obligates EPA to promulgate a FIP "at any time" within two years of disapproving a SIP submission or finding a State failed to submit a SIP. 42 U.S.C. § 7410(c)(1). Moreover, nothing in section 110(c) requires EPA to reveal to States the content (i.e., the emission reduction budgets) it intends to include in its FIP prior to proposing a FIP. Although the CAA allows States to submit SIPs to "correct[] the deficiency," they must do so "before" EPA's promulgation of a FIP, which may occur "at any time" within two years. Id.

The court thus rewrites section 110(c)(1)'s unambiguous grant of authority to EPA (and ultimate obligation of EPA) to promulgate a FIP at any time within the two year window to read: "unless but not until the State corrects the deficiency and the Administrator approves the [SIP] or [SIP] revision, before may the Administrator promulgates such [FIP]." "[A]s the Supreme Court has emphasized time and again, courts have no authority to rewrite the plain text of a statute." Kay v. FCC, 525 F.3d 1277, 1279 (D.C.Cir.2008). Because the CAA "means what it says," EPA was required, after publishing disapprovals and findings of failure to submit SIPs, to promulgate FIPs within two years, and it was not required to wait for States first to submit SIPs. Landstar Express Am. v. Fed. Maritime Comm'n, 569 F.3d 493, 498 (D.C.Cir.2009). The court's attempt to ferret out an argument about "simultaneity" as a distinct challenge properly brought against the Transport Rule based on EPA's interpretation of section 110(a) is thus a straw man for its endorsement of State petitioner's collateral attack on EPA's interpretation of section 110(a) in the Final SIP Rules. Its rewriting of section 110(c) is made all the more remarkable by its recognition that "we must apply and enforce the statute as it's now written." Op. at 12.

B.

Even if the court had jurisdiction over State petitioners' challenge to their independent obligation to submit "good neighbor" SIPs under CAA section 110(a), its statutory analysis proceeds with no regard for the plain text and structure of the CAA or for the deference owed to permissible agency interpretations of statutes they administer where Congress has left a gap for the agency to fill or the statute is ambiguous.

"As in all statutory construction cases," the court must "begin with the language of the statute." Barnhart v. Sigmon Coal Co., Inc., 534 U.S. 438, 450, 122 S.Ct. 941, 151 L.Ed.2d 908 (2002). "[C]ourts must presume that a legislature says in a statute what it means and means in a statute what it says there. When the words of a statute are unambiguous, then, this first canon is also the last: judicial inquiry is complete." Id. at 461-62, 122 S.Ct. 941 (quoting Connecticut Nat. Bank v. Germain, 503 U.S. 249, 253-54, 112 S.Ct. 1146, 117 L.Ed.2d 391 (1992) (internal quotation marks and citation omitted)). Thus, under Chevron U.S.A. Inc. v. Natural Res. Def. Council, 467 U.S. 837, 842-44, 104 S.Ct. 2778, 81 L.Ed.2d 694 (1984), the first step in statutory interpretation requires a determination of "whether Congress has directly spoken to the precise question at issue. If the intent of Congress is clear, that is the end of the mater; for the court, as well as the agency, must give effect to the unambiguously expressed intent of Congress," id. If, after applying traditional tools of statutory construction, the court determines "the statute is silent or ambiguous with respect to the specific issue," then, under step two, the court will defer to an agency's statutory interpretation if it "is based on a permissible construction of the statute." Id. at 843, 104 S.Ct. 2778.

The questions regarding States' obligations to submit "good neighbor" SIPs are straightforward: (1) Do States have an independent obligation to submit SIPs with adequate "good neighbor" provisions; (2) if so, what triggers that obligation; (3) if there is an obligation, what is the deadline for the SIP submission; and (4) must EPA prospectively quantify each States' amount of "significant contribution" to downwind nonattainment? The plain text of the statute provides equally straightforward answers: (1) Yes; (2) promulgation of a NAAQS; (3) within three years of promulgation of a NAAQS (unless the EPA Administrator prescribes a shorter deadline); and (4) no, but EPA may do so if it chooses.

Section 109 of the CAA requires EPA to promulgate NAAQS, a national health-based standard. See 42 U.S.C. § 7409. Section 110, in turn, provides that

Id. §§ 7410(a)(1) & (a)(2)(D)(i)(I) (emphases added). The plain text requires that within three years of EPA's promulgation of a NAAQS, States shall submit SIPs, and those SIPs shall include adequate "good neighbor" provisions. This is the unambiguous obligation and chronology established by Congress. EPA has the first duty to set the NAAQS, and then States have series of follow-up duties, listed in section 110(a), to ensure attainment of the NAAQS. Among the duties clearly assigned to States is the inclusion in SIPs of adequate "good neighbor" provisions.

The court views this "interpretation" — that is, reading the actual text of the statute — as a scene from Alice in Wonderland. See Op. at 33. It concludes that "[i]n our view, determining the level of reductions required under Section 110(a)(2)(D)(i)(I) is analogous to setting a NAAQS. And determining the level of reductions under the "good neighbor" provision triggers a period during which States may submit SIPs." Id. at 33. Even if the court's analogy were sound,8 the premise of its analogy does not support its conclusion that EPA's determination of emission reduction obligations triggers States' obligations to submit "good neighbor" SIPs. Rather, the court rewrites a decades-old statute whose plain text and structure establish a clear chronology of federal and State responsibilities. Nowhere does the CAA place a requirement on EPA to quantify each State's amount of "significant contribution" to be eliminated pursuant to the "good neighbor" provision, let alone include any provision relieving States of their "good neighbor" SIP obligations in the event EPA does not first quantify emission reduction obligations.9 The court's "view" that EPA "determining the level of reductions under the "good neighbor" provision triggers the period during which States may submit SIPs" is irrelevant in view of the unambiguously plain text of section 110(a)(1) and (a)(2)(D)(i)(I), and, if the statute were ambiguous, the court would be required to defer to EPA's interpretation that States have an independent obligation to submit "good neighbor" SIPs within three years of promulgation of the NAAQS because that interpretation is permissible under the statute, see Chevron, 467 U.S. at 843, 104 S.Ct. 2778. The court's "role is `not to `correct' the text so that it better serves the statute's purposes'; nor under Chevron may [the court] `avoid the Congressional intent clearly expressed in the text simply by asserting that [the court's] preferred approach would be better policy. The Congress has spoken plainly...." Virginia Dep't of Med. Assistance Servs. v. Dep't of Health & Human Servs., 678 F.3d 918, 926 (D.C.Cir.2012) (quoting Engine Mfrs. Ass'n v. EPA, 88 F.3d 1075, 1089 (D.C.Cir.1996)).

Furthermore, the court's holding is entirely at odds with the holding in Michigan v. EPA, 213 F.3d 663 (D.C.Cir.2000), see LaShawn A. v. Barry, 87 F.3d 1389, 1395 (D.C.Cir.1996) (en banc). In Michigan, State petitioners contended that EPA violated the CAA by prospectively informing States what their nitrogen oxides (NOx) emission reduction budgets needed to be to adequately eliminate their amounts of "significant contribution" under the "good neighbor" provision, thus acknowledging their independent obligation to submit adequate "good neighbor" SIPs, see 213 F.3d at 686-87. State petitioners in Michigan argued that EPA had no authority to do what the State petitioners now before the court contend EPA has no authority not to do. In Michigan the court deferred, pursuant to Chevron step two, to EPA's interpretation it could set State emissions budgets prospectively, given section 110's "silence" on the question, as a permissible exercise of EPA's general rulemaking authority under CAA section 301(a)(1), 42 U.S.C. § 7601(a)(1).10 Inverting Michigan's analysis of section 110, the court holds that under Chevron step one, see Op. at 34 n.32, section 110 itself unambiguously requires EPA to prospectively inform States of their "good neighbor" emission reduction requirements. See id. at 31-35. Nothing in section 110, section 301, or any other section of the CAA requires EPA to do this. Instead the court today turns "may" into "must," and holds that if EPA does not exercise its general rulemaking authority in the manner of the court's design, then section 110(a)(1)'s and 110(a)(2)(D)(i)(I)'s mandatory, unambiguous requirements that States submit adequate "good neighbor" SIPs within three years of the promulgation of a NAAQS are erased from the statute by judicial fiat — relieving States of the duty Congress imposed.11 The court offers no explanation for how its holding can be squared with Michigan in this regard.

The court's rationale for rewriting the CAA's plain text is its own conclusion that "the upwind State's obligation remains impossible for the upwind State to determine until EPA defines it." Id. at 32 (first emphasis added). In its words, the statute "requires each State to take its own stab in the dark ... [and] apply [a] homemade definition using its own homemade methodology." Id. at 35. The court concludes EPA's interpretation (that is, following the statute's plain text) produces absurd results, see id. at 34 n.32. Pretermitting whether there is a shred of record evidence to show such an impossibility, a statutory outcome is absurd [only] if it defies rationality[;] ... an outcome so contrary to perceived social values that Congress could not have intended it." Landstar Express, 569 F.3d at 498-99 (internal quotation marks and citations omitted) (emphases added). To the extent the court's rationale hinges on its speculation that States lack technical capability and information, this blinks at reality. As counsel for EPA emphasized at oral argument, see Tr. Oral Arg. at 59, 61, without contradiction by any petitioners' counsel during rebuttal oral argument, States are fully capable of measuring interstate transport of emissions by conducting modeling, and they have done so before and continue to do so: "The states can make that effort, and they can submit SIPs to EPA. Again, that is how the process works in the states that aren't included in these transport regions." Id. at 61. Indeed, as this court has recognized, States are charged with operating air quality monitors; "[e]xhaustive technical specifications regulate the States' operation of a network of air monitors that collect air quality data for any given area." Catawba Cnty., N.C. v. EPA, 571 F.3d 20, 30 (D.C.Cir.2009); cf. ATK Launch Sys. v. EPA, 669 F.3d 330, 334 (D.C.Cir.2012). The air quality monitoring data collected by the States is publically available in the National Emissions Inventory.12 That is, State air quality divisions are no strangers to complex air quality and meteorological modeling of interstate transport of emissions.13

No petitioner suggests that States lack the capability to measure their interstate emissions of pollutants or to access that information from other States to independently determine emission reduction budgets, much less that they have not had time to do so; rather their reason for not doing so appears to stem from insistence (supported by industry sources) that their reduction of emissions not be one iota greater than is necessary for downwind States to attain and maintain NAAQS and that it is easier (and presumably less costly, see Oral Arg. Tr. 58) for EPA to figure this out than it is for the individual States to do so, working cooperatively and using any EPA guidance. This may be so but it does not demonstrate that Congress's scheme, protecting States' choices about how to meet NAAQS requirements, in part by independently determining ways to meet their "good neighbor" obligation as the States argued in Michigan, is absurd.

It is true, as the court notes, see Op. at 34-35, that in two previous "good neighbor" rulemakings EPA afforded States the opportunity to submit SIPs after announcing emission reduction budgets. But an agency is not forever restricted to its previous policy choices or statutory interpretations; instead, it may change course provided it acknowledges it is doing so, presents "good reasons" for doing so, and its approach is "permissible under the statute." FCC v. Fox Television Stations, Inc., 556 U.S. 502, 515, 129 S.Ct. 1800, 173 L.Ed.2d 738 (2009). Agencies "need not demonstrate to a court's satisfaction that the reasons for the new policy are better than the reasons for the old one." Id. The discretion agencies enjoy in modifying their policy approaches is particularly expansive where the agency declines to exercise its discretionary rulemaking authority, as EPA did here. "It is only in the rarest and most compelling of circumstances that this court has acted to overturn an agency judgment not to institute rulemaking." WWHT, Inc. v. FCC, 656 F.2d 807, 818 (D.C.Cir.1981).

Here, EPA acknowledged its previous approach, see Transport Rule, 76 Fed. Reg. at 48,217; NPRM, 75 Fed. Reg. at 45,222-223, and explained its decision in response to comments requesting States be given time to submit SIPs before EPA imposed the Transport Rule FIPs. EPA stated, first, that it had no authority to alter the statutory deadlines for SIP submissions and that the CAA did not require it to issue a rule quantifying States' "good neighbor" obligations, see Transport Rule, 76 Fed. Reg. at 48,220; second, that the court in North Carolina, in remanding rather than vacating CAIR, "emphasized EPA's obligation to remedy [CAIR's] flaws expeditiously" and thus "EPA d[id] not believe it would be appropriate to establish a lengthy transition period to the rule which is to replace CAIR," Transport Rule, 76 Fed. Reg. at 48,220; and third, that in North Carolina this court also required EPA to align upwind States' emission reduction deadlines with the NAAQS attainment dates of "2015 or earlier," see North Carolina, 531 F.3d at 930.14 EPA's decision to adhere to the plain text of the statute, and not to exercise its discretionary general rulemaking authority, see Michigan, 213 F.3d at 686-87, was thus well-explained by the time pressures imposed by this court. See Fox Television, 556 U.S. at 515, 129 S.Ct. 1800. Inasmuch as those time pressures were animated as well by concern for the public health and welfare — Congress required that attainment with the NAAQS occur "as expeditiously as practicable." 42 U.S.C. §§ 7502(a)(2)(A) & 7511; see North Carolina, 531 F.3d at 930 — the instant case is particularly ill-suited for overturning EPA's exercise of its discretion in not adding an additional rulemaking step to the process. Given that the court "will overturn an agency's decision not to initiate a rulemaking only for compelling cause," and one of those few compelling reasons is when the decision declining to promulgate a rule exacerbates "grave health and safety problems for the intended beneficiaries of the statutory scheme," Midwest Indep. Transmission Sys. Operator, Inc. v. FERC, 388 F.3d 903, 911 (D.C.Cir.2004) (internal quotation marks and citation omitted), it hardly makes sense for the court to require EPA to promulgate a rule when the effect will be to delay health benefits. Indeed, the court is most reluctant to require agencies to promulgate rules "when the interests at stake are primarily economic," id., and the court's view that it is "impossible" for States to comply with their independent "good neighbor" obligation under section 110(a) is animated by the burdens that obligation imposes on States and industry sources, see Oral Arg. Tr. 58.

In sum, the court's conclusion that it would have been a "homemade" "stab in the dark" for the States to submit adequate "good neighbor" SIPs prior to promulgation of the Transport Rule lacks a basis in fact, and the court's speculation that EPA would have inevitably disapproved such submissions, see Op. at 36, is just that — speculation. And if that happened, States could judicially challenge the disapprovals, seeking a stay to avoid application of the Transport Rule FIPs. Absent record evidence to suggest that the plain text of the CAA's "good neighbor" SIP obligation on States leads to "an outcome so contrary to perceived social values that Congress could not have intended it," Landstar Express, 569 F.3d at 498-99 (internal quotation marks and citations omitted) (emphasis added), the court is bound, in view of the host of responsibilities placed on States in the CAA, to enforce the statute as Congress wrote it in plain terms, to give deference to EPA's permissible interpretations where the CAA is silent or ambiguous, and to adhere to the court's interpretation of EPA's authority in Michigan, as well as acknowledge, as the expert agency has advised without contradiction, that States have demonstrated competence to satisfy their plain statutory "good neighbor" obligations.

II.

The court also is without jurisdiction to hold that EPA lacked statutory authority to use a different measure of "significant contribution" for setting emission reduction budgets, unrelated to its measure of "significance" for purposes of threshold inclusion of individual States in the Transport Rule. Op. at 25-27. Petitioners contended that there was a hypothetical possibility that "application of cost-effective controls [] could drive a State's emissions below the point that, under phase one, would have excluded the State from any regulation whatsoever." State Petrs' Br. at 35; Industry & Labor Petrs' Br. at 22-24.15 Because no objection was made during the Transport Rule administrative proceedings to EPA's statutory authority to adopt its two-step approach, the court thus lacks jurisdiction to decide this issue. See CAA § 307(d)(7)(B), 42 U.S.C. § 7607(d)(7)(B). The jurisdictional question is not close; the court's effort to avoid this court's well-settled precedent fails clearly.

A.

Section 307(d)(7)(B) of the CAA provides that "[o]nly an objection to a rule or procedure which was raised with reasonable specificity during the period for public comment ... may be raised during judicial review." 42 U.S.C. § 7607(d)(7)(B) (emphasis added). The court has "`strictly' enforce[d] this requirement," Mossville Envtl. Action Now v. EPA, 370 F.3d 1232, 1238 (D.C.Cir.2004) (quoting Motor & Equip. Mfrs. Ass'n v. Nichols, 142 F.3d 449, 462 (D.C.Cir.1998)); see also Natural Res. Def. Council v. EPA, 571 F.3d 1245, 1259 (D.C.Cir.2009). The court also has made clear that "[r]easonable specificity requires something more than a general challenge to EPA's approach." Mossville, 370 F.3d at 1238 (internal quotation marks and alteration omitted). The court's enforcement of this requirement has been most strict in the context of statutory authority objections:

Cement Kiln Recycling v. EPA, 255 F.3d 855, 860 (D.C.Cir.2001) (quoting Natural Res. Def. Council, Inc. v. EPA, 25 F.3d 1063, 1074 (D.C.Cir.1994)) (emphasis added). Consistently, until now, the court has held that failure to object specifically to EPA's lack of statutory authority is grounds for dismissal of such objections in this court. See, e.g., Natural Res. Def. Council v. EPA, 559 F.3d 561, 563-64 (D.C.Cir.2009); Engine Mfrs. Ass'n v. EPA, 88 F.3d 1075, 1097 (D.C.Cir.1996); Ohio v. EPA, 997 F.2d 1520, 1528 (D.C.Cir.1993); Linemaster Switch Corp. v. EPA, 938 F.2d 1299, 1308 (D.C.Cir. 1991); Natural Res. Def. Council v. Thomas, 805 F.2d 410, 427 (D.C.Cir.1986).

Notably on point, in Cement Kiln the court held that comments stating a policy preference to EPA were insufficient to preserve for judicial review objections that the preferred approach was statutorily required, 255 F.3d at 860-61. "[T]hese comments merely argued that EPA could permissibly consider [the approach], not (as petitioners now argue) that [the CAA] requires [the approach]." Id. at 860 (internal quotation marks and citation omitted) (emphases in original). And "the parties were not saved by the fact that they had made other technical, policy, or legal arguments before the agency. Indeed, if such were the rule, a party could never waive a legal claim as long as the party in fact appeared and argued something before the agency." Nat. Res. Def. Council, 25 F.3d at 1074 (internal quotation marks omitted) (emphasis added).

Petitioners rely on two comments in an attempt to show a challenge to EPA's statutory authority to the approach it adopted was presented during the Transport Rule administrative proceedings. See Industry & Labor Petrs.' Reply Br. at 6, n.1. Neither is sufficient. Tennessee commented that "[a] lower cost threshold should be considered for any State that can reduce their contribution below 1% significance using cost thresholds below the maximum values ($2,000/ton for SO2 and $500/ton for NOx), if applicable." Tennessee Comments on 2010 Proposed Transport Rule, Attachment 1, at 1 (Aug. 27, 2010). But this comment does not suggest that EPA is statutorily barred from following its approach. See Cement Kiln, 255 F.3d at 860-61; Natural Res. Def. Council, 25 F.3d at 1073-74. Furthermore, Tennessee's comment does not even suggest a policy preference that the one percent of NAAQS threshold level be a floor. Rather, Tennessee's comment specifically mentions States reducing contributions below the threshold without suggesting that result would violate the CAA. Thus, the only thing Tennessee commented on with "reasonable specificity" was that EPA consider not using a uniform cost threshold for all States.

Wisconsin's comment also does not demonstrate the statutory authority challenge now advanced by petitioners in this court was preserved. First, Wisconsin stated that it "support[ed] the 1% contribution threshold ... for identifying states that are significant contributors to downwind state's air quality nonattainment and maintenance problems." Wisconsin Comments, at 1 (Oct. 1, 2010). Wisconsin further stated:

Id. at 7 (emphases added). Wisconsin nowhere suggested that EPA is statutorily required to use the one percent inclusion threshold as a floor for emission reductions; it simply urged that EPA "should" put a "greater emphasis" on air quality impacts at the individual EGU level. Indeed, Wisconsin commented that the cost threshold was too low, the exact opposite of what petitioners now claim. See Industry & Labor Petrs.' Br. at 31-34. The closest Wisconsin comes to raising a statutory authority argument is its statement that the "issues are [] legal;" but that vague comment is in a sentence indicating the State's preference that EPA regulate at the EGU, rather than the State level, in order to achieve "EGU system control installation equity." Wisconsin Comments, at 7.

Consequently, neither Tennessee's nor Wisconsin's comments argued "with reasonable specificity" that EPA was statutorily required to treat the threshold inclusion level in its two-step approach to defining "significant contribution" as a floor in calculating emission reduction requirements.16 Nor do they even present a policy preference for such an approach and, indeed, can be interpreted as supporting sub-threshold reductions. Even if the comments implied a challenge, which they do not, an implied challenge is insufficient because

Mossville, 370 F.3d at 1239-40. None of the comments during the Transport Rule administrative proceedings approaches the level of "reasonable specificity" required for this court to have jurisdiction over petitioners' new statutory authority argument.

B.

Acknowledging this, the court nonetheless concludes that it has jurisdiction to address this new issue because "EPA was on notice that its disregard of the significance floor was a potential legal infirmity in its approach." Op. at 25 n.18. None of the three reasons the court offers for its conclusion that there need not be objections raised "with reasonable specificity during the period for public comment," 42 U.S.C. § 7607(d)(7)(B), is convincing.

First, the court states that EPA was required "to craft a new rule consistent with [North Carolina]," Op. at 24 n.18 (internal quotation marks and citation omitted), and thus should have been alerted to petitioners' new objection, raised for the first time now in this court. But in North Carolina the court specifically permitted the exact same approach in CAIR. Discussing this approach, the court explained:

North Carolina, 531 F.3d at 916-17 (emphases added). There is no basis to conclude that EPA acted inconsistently with North Carolina by replicating the approach the court left undisturbed. It is true that in North Carolina the court rejected EPA's use of fuel factors in allocating allowances for the CAIR trading program because doing so redistributed reduction responsibilities to the benefit of States with more coal-fired electricity generation, see id. at 920-21. The court stated that EPA

Id. at 921 (emphases added). But a holding that EPA had acted arbitrarily in designing its trading program cannot fairly be deemed to alert EPA that it might exceed its statutory authority in using an approach to measuring "significant contribution" that the court specifically declined to disturb. Cf. Natural Res. Def. Council v. EPA, 571 F.3d 1245, 1259 (D.C.Cir.2009) ("EPA cannot be expected to take [an] argument, raised in support of one specific objection, and apply it sua sponte to another provision."). EPA was entitled, in the absence of objection in the Transport Rule administrative proceedings, to rely in promulgating the Transport Rule upon the court's decision not to disturb its approach. And the fact that after North Carolina no comment in the Transport Rule administrative proceedings objected that EPA was exceeding its statutory authority in adopting its approach underscores the fact that EPA was not acting inconsistently with North Carolina in light of a few sentences about fuel factors plucked out of context.

Second, reaching farther afield, the court points to a comment submitted during the CAIR rulemaking that it deems sufficient, when combined with the holding in North Carolina, to "show that EPA `had notice of this issue and could, or should have, taken it into account.'" Op. at 24 n.18 (quoting Natural Res. Def. Council v. EPA, 824 F.2d at 1146, 1151 (D.C.Cir. 1987)).17 The CAIR comment stated "that the threshold contribution level selected by EPA should be considered a floor, so that upwind States should be obliged to reduce their emissions only to the level at which their contribution to downwind nonattainment does not exceed that threshold level." CAIR, 70 Fed. Reg. 25,162, 25,176-77 (May 12, 2005). This comment, which was not cited in any petitioners' brief to this court but first mentioned by industry petitioners during rebuttal oral argument, cannot carry the weight the court assigns to it, particularly in light of the holding in North Carolina. The court generally does not entertain arguments raised for the first time in a reply brief, see Altman v. SEC, 666 F.3d 1322, 1329 (D.C.Cir.2011); North Carolina, 531 F.3d at 924 n. 6, let alone for the first time at oral argument, see Roth v. U.S. Dep't of Justice, 642 F.3d 1161, 1181 (D.C.Cir.2011); Ark Las Vegas Rest. Corp. v. NLRB, 334 F.3d 99, 108 n. 4 (D.C.Cir.2003), much less during rebuttal oral argument, see Coalition of Battery Recyclers Ass'n, 604 F.3d at 623; Old Dominion Dairy Products, Inc. v. Sec. of Defense, 631 F.2d 953, 961 n. 17 (D.C.Cir. 1980). The reason is simple: "in order to prevent `sandbagging of appellees and respondents,' we do not consider arguments that were raised neither in the opening brief nor by respondents." S. Coast Air Quality Mgmt. Dist. v. EPA, 554 F.3d 1076, 1081 n.* (D.C.Cir.2009) (quoting Sitka Sound Seafoods, Inc. v. NLRB, 206 F.3d 1175, 1181 (D.C.Cir.2000)). Here that reason has particular resonance because EPA was relying on the court's decision in North Carolina, 531 F.3d at 916-17, to "not disturb" its two-step approach to defining "significant contribution," and no one referenced the CAIR comment during the Transport Rule administrative proceedings.

Even setting aside the starkly novel forfeiture standard the court has chosen to apply to industry petitioners, the cited CAIR comment is insufficient to establish that the issue of EPA's statutory authority was properly preserved for the court to have jurisdiction to address it. The court relies on a footnote in American Petroleum Institute v. EPA, 52 F.3d 1113, 1120 n. 1 (D.C.Cir.1995), for the proposition that it is "highly relevant" if an agency previously "reject[ed] [] the same argument in a prior rulemaking," Op. at 24 n.18. Although the CAIR comment communicates a policy preference, this court has distinguished between comments presenting policy preferences and those presenting statutory authority objections, see, e.g., Cement Kiln, 255 F.3d at 860-61, and technical and policy arguments are insufficient to preserve objections to EPA's statutory authority. See Nat. Res. Def. Council, 25 F.3d at 1074. The CAIR comment that EPA rejected in the other rulemaking is therefore not "the same argument" that petitioners belatedly attempt to raise now. Furthermore, in American Petroleum, the court concluded that the jurisdictional question was "close" inasmuch as EPA had explicitly incorporated the docket from the previous rulemaking in the second rulemaking, and the previous rulemaking had been aborted, such that there was no intervening opportunity for judicial review. See Am. Petroleum, 52 F.3d at 1120 n. 1. Neither of those factors that made American Petroleum a close case is present here. The Transport Rule was promulgated to replace CAIR, but the CAIR docket was never incorporated into the Transport Rule docket — perhaps because of the court's instruction in North Carolina that EPA "redo its analysis from the ground up." 531 F.3d at 929. EPA would have had no reason to reexamine the voluminous CAIR docket in search for objections that were not raised before the court in North Carolina. Also, unlike the aborted rule whose docket EPA incorporated in American Petroleum, in CAIR there was an intervening opportunity for judicial review. Yet no one sought judicial review of CAIR on the basis of the CAIR comment now relied on by the court. This precise circumstance was relied upon by the court in North Carolina in declining to disturb EPA's approach. See id. at 917; see Med. Waste, 645 F.3d at 427.18 Once the court in North Carolina declined to disturb EPA's approach, because no objection to EPA's authority to adopt its approach had been raised to the court, petitioners were required to inform EPA during the Transport Rule administrative proceedings that they objected to EPA's statutory authority to pursue that approach. See 42 U.S.C. § 7607(d)(7)(B). If American Petroleum presented a "close" jurisdictional question, then the jurisdictional question here is easily decided.

Third, the court concludes that "EPA's statements at the proposal stage indicated EPA was not open to reconsidering CAIR's earlier rejection of petitioners' argument," and that because EPA had dismissed "the two air quality-only approaches it considered," the comments of Tennessee, Wisconsin, and Delaware were "`reasonable' under the circumstances," Op. at 24, n.18. But there was no such "earlier rejection of petitioners' argument" in CAIR because the CAIR comment did not suggest that EPA exceeded its statutory authority by following its two-step approach to defining "significant contribution." See Cement Kiln, 255 F.3d at 860-61. Furthermore, industry petitioners acknowledge in their Reply Brief that they "are not advocating an `air quality-only' approach," but instead a cost-based approach with a floor for emission reduction obligations. Industry & Labor Petrs' Reply Br. at 10. So, EPA's rejection of two alternative air quality-only approaches has no bearing on whether EPA would have been willing to entertain an objection during the Transport Rule administrative proceedings that the "good neighbor" provision required it to use the threshold level for a State's inclusion in the Transport Rule as a floor for emission reduction obligations.

Nothing in this court's precedent on CAA section 307(d)(7)(B), 42 U.S.C. § 7607(d)(7)(B), supports the court's tortured efforts to avoid the jurisdictional limits in the CAA and seize jurisdiction where petitioners clearly fall far short of preserving their claim by objecting to EPA's statutory authority during the Transport Rule administrative proceedings with "reasonable specificity." The court does not acknowledge this court's precedent setting a strict standard for preservation of statutory authority objections, which demonstrates the inconsistency of the court's exercise of jurisdiction today. See, e.g., Natural Res. Def. Council, 559 F.3d at 563-64; Am. Farm Bureau Fed'n v. EPA, 559 F.3d 512, 538 (D.C.Cir.2009); Natural Res. Def. Council v. EPA, 571 F.3d 1245, 1259 (D.C.Cir.2009); Mossville, 370 F.3d at 1238; Cement Kiln, 255 F.3d at 860-61; George E. Warren Corp. v. EPA, 159 F.3d 616, 629 (D.C.Cir.1998); Motor & Equip. Mfrs. Ass'n, 142 F.3d at 462; Natural Res. Def. Council, 25 F.3d at 1074; Ohio v. EPA, 997 F.2d at 1528-29; Natural Res. Def. Council v. EPA, 937 F.2d 641, 647-48 (D.C.Cir.1991); Linemaster Switch Corp., 938 F.2d at 1308; Thomas, 805 F.2d at 425-27; Lead Indus. Ass'n, 647 F.2d at 1173.

Rather than confront the force of this precedent, the court relies on phrases from a few opinions suggesting a more flexible standard, see Op. at 24-25 n.18, but tellingly omits any discussion of the analyses or outcomes in those cases. This is because even where the court has mentioned flexibility, the comments at issue were either significantly more specific than the comments of Tennessee and Wisconsin, and were thus sufficient, or were more specific but nonetheless deemed wanting. For example, in Natural Resources Defense Council v. EPA, 571 F.3d 1245, 1259 (D.C.Cir.2009), the court suggested there is "leeway" but concluded, in words that resonate here, that "EPA cannot be expected to take [an] argument, raised in support of one specific objection, and apply it sua sponte to another provision." Id. at 1259-60. The irony in the court's reliance on this case is that it expects EPA to read North Carolina in precisely the opposite manner — it concludes EPA should have taken a holding about "exceeding the mark" in the CAIR trading allowance program and sua sponte applied it to the methodology for calculating "significant contribution," even though the court explicitly declined to disturb that methodology. See supra Pt. II.B. In Appalachian Power, 135 F.3d 791, 817 (D.C.Cir.1998), the court concluded the "argument ... during the comment period [was] — in substance, if not in form, the same objection" raised before the court, whereas here the comments of Tennessee and Wisconsin did not raise the statutory authority objection now urged upon the court in either form or substance. The court also relies on Natural Resources Defense Council v. EPA, 824 F.2d 1146, 1150-51 (D.C.Cir.1987) (en banc), which involved common law exhaustion, not CAA section 307(d)(7)(B), and in that case the issue was "explicitly raised... in comments" before the EPA, id. at 1151. And although observing in South Coast Air Quality Management District v. EPA, 472 F.3d 882, 891-92 (D.C.Cir.2009), that petitioners have "some leeway," the court concluded that leeway did not permit the petitioner to rely upon a general procedural preference stated in a cover letter to its comments to alert EPA to the details of the objections to a final rule.

None of the court's proffered reasons for ignoring section 307(d)(7)(B)'s jurisdictional limitations has merit on its own, nor in combination. "[Z]ero plus zero [plus zero] equals zero." U.S. v. Clipper, 313 F.3d 605, 609 (D.C.Cir.2002).

III.

The court's remaining reasons for vacating the Transport Rule are also either beyond its jurisdiction or unpersuasive.

First, the court concludes that EPA violated the CAA by not calculating the required emission reductions "on a proportional basis that took into account contributions of other upwind States to the downwind States' nonattainment problems." Op. at 27. This is so, the court says, because in Michigan the court only permitted cost to be considered as a way "to allow some upwind States to do less than their full fair share," not more. Id. Petitioners have not argued that EPA violated the CAA by not calculating emission reductions on a proportional basis, as the court suggests. See Anna Jaques Hosp. v. Sebelius, 583 F.3d 1, 7 (D.C.Cir.2009). The statement in industry petitioners' brief that the court quotes, see Op. at 26, instead maintains that EPA was arbitrary and capricious in the way it grouped States for 2014 sulfur dioxide (SO2) budgets because, they claimed, EPA did so without "consider[ing] relative contributions of the various States," Industry & Labor Petrs' Br. at 33. This challenge is limited to the asserted arbitrariness of how certain States were categorized for one pollutant's budget for one year. The court lacks jurisdiction to consider sua sponte an objection to EPA's statutory authority not raised by petitioners within the sixty day period required under CAA section 307(b)(1), 42 U.S.C. § 7607(b)(1); see Med. Waste, 645 F.3d at 427. As this court has previously said, "[t]o rely on relief plaintiffs never requested on a claim they never made would be to conclude that zero plus zero equals more than zero." NAACP, Jefferson Cnty. Branch v. U.S. Sugar Corp., 84 F.3d 1432, 1438 (D.C.Cir.1996).

Second, even if petitioners had raised a "proportionality" statutory authority objection, this objection and the court's conclusion are premised on the speculative possibility that the Transport Rule might require States to reduce emissions to a level below the one percent of NAAQS inclusion threshold of EPA's two-step approach to defining "signification contribution," and thus more than their statutory fair share — an argument over which the court also lacks jurisdiction. See supra Part II. Further, the court's conclusion is at odds with North Carolina where the court concluded that EPA's measure of significant contribution need not "directly correlate with each State's individualized air quality impact on downwind nonattainment relative to other upwind states." 531 F.3d at 908 (emphasis added); see LaShawn A., 87 F.3d at 1395. It also ignores that in Michigan the court expressly permitted the use of uniform cost thresholds to measure "significance," and likewise permitted the "ineluctabl[e]" result of small and large contributors being required to make the same amount of reductions. 213 F.3d at 679. Without jurisdiction to reach an argument on whether the Transport Rule requires States to reduce more than their statutory fair share, Michigan requires the conclusion that EPA's choice of cost thresholds in the Transport Rule was permissible.

Next, the court concludes that EPA failed to consider the effect of in-State emissions of downwind States on their own nonattainment and interference with maintenance problems, see Op. at 57. Petitioners conceded at oral argument that this "in-State contribution" contention was "not actually an independent statutory authority argument," Oral Arg. Tr. at 32, but merely a repackaged version of the objection to the possibility of reductions below the one percent of NAAQS inclusion threshold, an argument over which the court lacks jurisdiction, see supra Part II. Even if the court had jurisdiction to address it, the court's conclusion is unsupported by the record. EPA examined the various cost threshold for each State, and in so doing considered

Transport Rule, 76 Fed. Reg. at 48,256 (emphases added); see id. at 48,259 (concluding remaining nonattainment problem in Liberty-Clairton was the result of local emissions). EPA thus in fact examined the contribution of downwind States to their own nonattainment problems.

Finally, the court concludes that EPA "did not try to take steps to avoid" collective over-control, Op. at 27. This conclusion too is unsupported by the record. The Transport Rule was not projected to achieve attainment of all downwind nonattainment and maintenance problems attributed to upwind States. See id. at 48,210, 48,232, 48,247-48; Resp.'s Br. at 38 n.24. Because EPA's analysis demonstrated instances of "remaining downwind air quality problems," Transport Rule, 76 Fed. Reg. at 48,256, there is no support for the court's conclusion that the Transport Rule resulted in collective over-control.

IV.

The Transport Rule, as EPA observes, represents "the culmination of decades of Congressional, administrative, and judicial efforts to fashion a workable, comprehensive regulatory approach to interstate air pollution issues that have huge public health implications." Resp.'s Br. at 12. The legislative history to amendments of the CAA documents Congress's frustration with the upwind States' historic failure to take effective action on their own to curtail their contributions to problems of pollution in downwind States, leading to amendments to strengthen EPA's hand. The court ignores Congress's limitations on the court's jurisdiction and decades of precedent strictly enforcing those limitations and proceeds to do violence to the plain text of the CAA and EPA's permissible interpretations of the CAA, all while claiming to be "apply[ing] and enforc[ing] the statute as it's now written." Op. at 12. The result is the endorsement of a "maximum delay" strategy for regulated entities, rewarding States and industry for cloaking their objections throughout years of administrative rulemaking procedures and blindsiding the agency with both a collateral attack on its interpretation of section 110(a) and an objection raised for the first time in this court, despite the court's previous decisions declining to disturb the approach EPA adopted in the Transport Rule.

To reach the result — vacating the Transport Rule — the court does several remarkable things. It seizes jurisdiction over the issue of States' independent "good neighbor" obligation by allowing States to pursue a collateral attack on Final SIP Rules from which they either failed timely to file petitions for review or their petitions challenging those rules have not been consolidated with the petitions challenging the Transport Rule that are before this three-judge panel. It asserts jurisdiction over industry's challenge to EPA's two-step approach to defining "significant contribution" by excusing industry from its failure to preserve the issue by first presenting it to EPA and then resting jurisdiction on a comment in another rulemaking that was first cited by industry in rebuttal oral argument and cannot bear the weight the court assigns to it because it did not challenge EPA's statutory authority to adopt its two-step approach. All this is contrary to Congress's limitations on the court's jurisdiction and this court's precedent enforcing those limitations. The rest of the court's analysis recalibrates Congress's statutory scheme and vision of cooperative federalism in the CAA. Along the way, the court abandons any consideration that an agency is entitled to repose, absent objection during its administrative proceedings, when a court, here on two occasion, expressly leaves undisturbed its two-step approach to enforcing a statute it administers and no objection is raised during the Transport Rule administrative proceedings. Then, in dictum, the court offers suggestions as to how EPA might fix the problems the court has created upon rewriting the CAA and trampling on this court's precedent in North Carolina and Michigan.

None of this is to suggest that EPA should be excused from the statutory limits on its authority or any material procedural missteps under the CAA or the APA. But neither can the court ignore jurisdictional limits or substantive provisions that Congress wrote in clear terms and EPA's permissible interpretations of the CAA in addressing statutory silence or ambiguity. Rather it underscores why, as a programmatic and public health matter, Congress concluded there are important reasons for jurisdictional limits and administrative exhaustion that this court heretofore has steadfastly acknowledged in recognizing both the limits of its jurisdiction and of its role in enforcing the CAA as Congress wrote it.

Accordingly, I respectfully dissent.