FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

LATINO ISSUES FORUM; SIERRA          
CLUB; and MEDICAL
ADVOCATES FOR HEALTHY AIR,
                      Petitioners,
                v.
UNITED STATES ENVIRONMENTAL                 No. 06-71907
PROTECTION AGENCY,                            EPA No.
                      Respondent,         EPA-1: Clean Air
               and                               Act
SAN JOAQUIN VALLEY UNIFIED AIR                OPINION
POLLUTION CONTROL DISTRICT;
ALLIANCE OF WESTERN MILK
PRODUCERS; and AIR COALITION
TEAM,
          Respondent-Intervenors.
                                     
        On Petition for Review of an Order of the
           Environmental Protection Agency

                 Argued and Submitted
       October 21, 2008—San Francisco, California

                     Filed March 5, 2009

    Before: J. Clifford Wallace, Sidney R. Thomas and
             Susan P. Graber, Circuit Judges.

                Opinion by Judge Graber;
              Concurrence by Judge Thomas



                            2741
2744             LATINO ISSUES FORUM v. EPA




                         COUNSEL

Paul Cort, Earthjustice, Oakland, California, for the petition-
ers.

Thomas A. Lorenzen and Christina B. Parascandola, United
States Department of Justice, Environment & Natural
Resources Division, Washington, D.C., for the respondent.
                 LATINO ISSUES FORUM v. EPA                2745
Philip M. Jay, District Counsel, San Joaquin Valley Unified
Air Pollution Control District, Fresno, California; David E.
Cranston, Greenberg Glusker Fields Claman & Machtinger
LLP, Los Angeles, California; and Rissa A. Stuart, Kahn,
Soares & Conway, LLP, Hanford, California, for the
respondent-intervenors.


                          OPINION

GRABER, Circuit Judge:

   Petitioners Latino Issues Forum and Sierra Club challenge
the Environmental Protection Agency’s (“EPA”) approval of
a revision to the state implementation plan (“SIP”) for San
Joaquin Valley, California. The revision, known as Rule
4550, is part of the Conservation Management Practices
(“CMP”) Program, an air-pollutant reduction program, estab-
lished by the San Joaquin Valley Unified Air Pollution Con-
trol District (“District”). Rule 4550 aims to reduce emissions
from agricultural sources of a certain kind of particulate mat-
ter known as PM-10. We hold that Rule 4550 comports with
the requirements of 42 U.S.C. §§ 7509 and 7513a(b)(1)(B)
and, therefore, deny the petition.

 STATUTORY AND REGULATORY BACKGROUND

   The Clean Air Act, 42 U.S.C. §§ 7401-7671 (“Act”), estab-
lishes a comprehensive program for controlling and improv-
ing the United States’ air quality through state and federal
regulation. The Act requires the EPA to establish national
ambient air quality standards (“NAAQS”) for air pollutants
that the EPA determines may reasonably be expected to
endanger public health or welfare. 42 U.S.C. §§ 7408, 7409.

  The states are responsible for ensuring that their air quality
meets the NAAQS. 

The states are divided into
2746              LATINO ISSUES FORUM v. EPA
“air quality control regions,” and each region is designated as
being either in attainment or nonattainment, or as unclassifi-
able with respect to each of the NAAQS. 

The
attainment deadlines and control measures applicable within
each region vary, depending on the pollutant and the severity
of the region’s pollution problem. See 

7509,
7511-7514a.

   Under the Act, a state must develop a SIP that provides for
the attainment, maintenance, and enforcement of the NAAQS
in each region within the state. 

Section 7410
sets forth the general requirements for all SIPs, which include
enforceable emission limitations and other control measures
to meet the requirements of the Act; enforcement programs;
and assurances that the state has adequate personnel, funding,
and authority to carry out the SIP. Every SIP or SIP revision
must be adopted by the state after reasonable notice and hear-
ing, and each must be submitted to the EPA for approval. 

The EPA may fully approve, partially approve
and partially disapprove, conditionally approve, or fully dis-
approve a SIP. 

The provisions of the
SIP that the EPA approves are federally enforceable. See 

   The EPA has established NAAQS for “particulate matter,”
that is, the particles found in the air, such as dust, dirt, soot,
smoke, and liquid droplets. Particles with a diameter less than
or equal to ten micrometers are known as PM-10. 40 C.F.R.
§ 50.6(c).

  On November 15, 1990, the date of enactment of the Clean
Air Act Amendments of 1990, Congress designated ten PM-
10 nonattainment areas, including the San Joaquin Valley,
across the country. 42 U.S.C. § 7407(d)(4)(B). All the PM-10
nonattainment areas were classified initially as “moderate”
PM-10 nonattainment areas with an attainment deadline of
December 31, 1994. 

56 Fed. Reg.
11,101 (Mar. 15, 1991). The EPA was authorized to reclassify
                  LATINO ISSUES FORUM v. EPA                 2747
a moderate nonattainment area as “serious” before the attain-
ment deadline if the EPA found that the area could not “prac-
ticably” attain the PM-10 NAAQS by the deadline. 42 U.S.C.
§ 7513(b)(1).

   The statutory requirements differ between moderate and
serious PM-10 nonattainment areas. 

Whereas
moderate PM-10 nonattainment plans must include
“reasonably available control measures” (“RACM”), 

(emphasis added), serious PM-10 nonattain-
ment plans must provide for the implementation of “best
available control measures” (“BACM”), 

(emphasis added). Additionally, plans for an area designated
as serious that does not reach attainment by the applicable
deadline must provide for attainment of the PM-10 standards
and for an annual reduction of PM-10 or PM-10 precursor
emissions by the date of an extended deadline. 

That annual reduction cannot be less than five percent of the
amount of such emissions, as reported in the most recent
inventory prepared for the area. 

does not define RACM or BACM. In 1992, the
EPA published a “General Preamble,” which is “an advance
notice of how EPA generally intends . . . to take action on SIP
submissions.” 57 Fed. Reg. 13,498-01, 13,498 (Apr. 16,
1992). In that document, the EPA set forth the process by
which RACM should be determined for inclusion in a
moderate-area SIP. The first step is to list all available control
measures. 

Second, the states must provide a rea-
soned justification for rejection of a particular RACM. 

control measures are then to be “evaluated for rea-
sonableness, considering their technological feasibility and
the cost of control in the area to which the SIP applies.” 

The control measures that are determined to be
reasonable are then considered RACM for the moderate PM-
10 area.

  The EPA set forth the standards for determining BACM in
an Addendum to the General Preamble. 59 Fed. Reg. 41,998
2748              LATINO ISSUES FORUM v. EPA
(Aug. 16, 1994). BACM is considered to be a higher level of
control than RACM because, “when comparing the terms
‘reasonable’ and ‘best’ as applied to control measures, the
word ‘best’ strongly implies that there should be a greater
emphasis on the merits of the measure or technology alone
and less flexibility in considering other factors.” 

The procedures prescribed by the EPA for determining
BACM include: (1) develop an inventory of the sources of
PM-10 and PM-10 precursor emissions; (2) evaluate, via
modeling, the effect of PM-10 concentrations of various
sources to determine which are significant sources; (3) evalu-
ate the technological and economic feasibility of the potential
control measures; and (4) evaluate the costs and energy and
environmental impacts of potential BACM. 

   FACTUAL AND PROCEDURAL BACKGROUND

   The San Joaquin Valley, which is located in Central Cali-
fornia, comprises approximately 25,000 square miles and
includes the counties of Fresno, Kings, Tulare, San Joaquin,
Stanislaus, Madera, and Merced, plus a portion of Kern
County. The San Joaquin Valley is bordered by the Sierra
Nevada range on the east, the Coast Mountain range on the
west, and the Tehachapi Mountains on the south.

   The Clean Air Act Amendments of 1990 designated San
Joaquin Valley as a moderate nonattainment area for PM-10.
42 U.S.C. § 7407(d)(4)(B); see 56 Fed. Reg. at 11,103. The
Clean Air Act Amendments of 1990 required the District to
submit to the EPA the first of its moderate nonattainment plan
elements by November 15, 1991. 42 U.S.C. § 7513a(a)(2)(A).
The District failed to meet that deadline; consequently, the
EPA determined that the PM-10 pollution problems in the San
Joaquin Valley were too severe to resolve by the December
31, 1994, statutory deadline for moderate areas. See 58 Fed.
Reg. 3,334-01, 3,334 (Jan. 8, 1993). Thus, the EPA reclassi-
fied the San Joaquin Valley as a serious nonattainment area
for PM-10 effective February 8, 1993, thus extending the
                 LATINO ISSUES FORUM v. EPA                2749
deadline for attainment to December 31, 2001. 

3,337. The District was required to submit a revised SIP no
later than February 8, 1997. 42 U.S.C. § 7513a(b)(2).

   The District submitted to the EPA two proposed SIPs, the
first in 1994 and the second in 1997. See 67 Fed. Reg.
11,925-01, 11925-26 (Mar. 18, 2002). The EPA intended to
disapprove each of those plans but, just as the EPA was pre-
paring each proposed disapproval notice, the District
informed the EPA that it had withdrawn both plans from con-
sideration by the EPA. 

Accordingly, on Febru-
ary 28, 2002, the EPA issued a finding that the state had failed
to submit a SIP for the San Joaquin Valley serious PM-10
nonattainment area. 

19, 2003, the District submitted to the EPA a
revised SIP to satisfy the requirements of section 189(b)-(d)
of the Clean Air Act. 42 U.S.C. § 7513a(b)-(d); 69 Fed. Reg.
5,412-01, 5,413 (Feb. 4, 2004). The EPA partially approved
the District’s revised plan, 69 Fed. Reg. 30,006-01 (May 26,
2004), but stated that it would act at a later date on the ele-
ments missing from the District’s revised plan, including
measures to control PM-10 emissions from agricultural
sources, 

Because the last deadline for attain-
ment had passed, the EPA established 2010 as the earliest
date by which the San Joaquin Valley could practicably attain
the PM-10 standards. 

   On August 19, 2004, the District adopted Rule 4550 and its
associated CMP list. 70 Fed. Reg. 16,207-01 (Mar. 30, 2005).
Rule 4550 applies to PM-10 emissions from agricultural oper-
ations with 100 or more contiguous acres and from concen-
trated animal feeding operations that meet or exceed certain
minimum size requirements. 

The Rule
requires those agricultural operations to choose one control
practice from each of five categories for cropland and poultry
operations, and one from each of four categories for beef and
dairy operations. 

Each category presents a menu
2750              LATINO ISSUES FORUM v. EPA
of as many as 24 different control options from which the
source can choose to comply with the rule. 

the
various menus list more than 100 potential control measures.

submitted Rule 4550 to the EPA for approval
on September 23, 2005. See 70 Fed. Reg. 16,207-01 (Mar. 30,
2005). The EPA proposed approval of the rule on March 30,
2005, and published its final notice approving the rule on Feb-
ruary 14, 2006. See 71 Fed. Reg. 7,683-01, 7,683-88 (Feb. 14,
2006). Petitioners then challenged the EPA’s adoption of Rule
4550 by filing a timely petition for review in this court. We
have jurisdiction pursuant to 42 U.S.C. § 7607(b)(1).

                STANDARD OF REVIEW

   Title 42 U.S.C. § 7607(b)(1), which gives us jurisdiction to
review the EPA’s approval of Rule 4550, does not specify a
standard of review, so we apply the general standard of
review for agency actions set forth in the Administrative Pro-
cedure Act (“APA”), 5 U.S.C. §§ 701-706. Vigil v. Leavitt,

, 833 (9th Cir. 2004). Under the APA, we con-
sider whether the EPA’s action was “arbitrary, capricious, an
abuse of discretion, or otherwise not in accordance with law.”
5 U.S.C. § 706(2)(A). This standard requires the EPA to “ar-
ticulate[ ] a rational connection between the facts found and
the choice made.” Ariz. Cattle Growers’ Ass’n v. U.S. Fish &
Wildlife, 

, 1236 (9th Cir. 2001).

  We have held:

    [C]ourts must carefully review the record to ensure
    that agency decisions are founded on a reasoned
    evaluation of the relevant factors, and may not
    rubber-stamp . . . administrative decisions that they
    deem inconsistent with a statutory mandate or that
    frustrate the congressional policy underlying a stat-
                  LATINO ISSUES FORUM v. EPA                 2751
    ute . . . . Nevertheless, we may not substitute [our]
    judgment for that of the agency . . . .

Friends of Yosemite Valley v. Norton, 

, 793 (9th
Cir. 2003) (alterations in original) (citation and internal quota-
tion marks omitted). In particular, “where, as here, a court
reviews an agency action ‘involv[ing] primarily issues of
fact,’ and where ‘analysis of the relevant documents requires
a high level of technical expertise,’ we must ‘defer to the
informed discretion of the responsible federal agencies.’ ”
Sierra Club v. EPA, 

, 961 (9th Cir. 2003) (alter-
ation in original) (quoting Marsh v. Or. Natural Res. Council,

, 377 (1989)). “Even when an agency explains
its decision with ‘less than ideal clarity,’ ” we “will not upset
the decision on that account ‘if the agency’s path may reason-
ably be discerned.’ ” Alaska Dep’t of Envtl. Conservation v.
EPA, 

, 497 (2004) (quoting Bowman Transp.,
Inc. v. Ark.-Best Freight Sys., Inc., 

, 286 (1974)).

   In reviewing a decision made by an administrative agency,
our “proper role is simply to ensure that the [agency] made no
‘clear error of judgment’ that would render its action ‘arbi-
trary and capricious.’ ” Lands Council v. McNair, 

, 993 (9th Cir. 2008) (en banc) (quoting 

). We are to be “most deferential” when the agency
makes “predictions, within its [area of] special expertise, at
the frontiers of science.” Forest Guardians v. U.S. Forest
Serv., 

, 1099 (9th Cir. 2003). We are “not free
to ‘impose upon the agency [our] own notion of which proce-
dures are “best” or most likely to further some vague, unde-
fined public good.’ ” Churchill County v. Norton, 

, 1072 (9th Cir. 2001) (alteration in original) (quoting Vt.
Yankee Nuclear Power Corp. v. Natural Res. Def. Council,
Inc., 

, 549 (1978)).

   On questions of statutory interpretation, we follow the two-
step approach set out in Chevron U.S.A. Inc. v. Natural
Resources Defense Council, Inc., 

(1984). First,
2752              LATINO ISSUES FORUM v. EPA
we employ “traditional tools of statutory construction” to
determine whether Congress has expressed its intent unam-
biguously on the question before the court. 

n.9. “If
the intent of Congress is clear, that is the end of the matter;
for the court, as well as the agency, must give effect to the
unambiguously expressed intent of Congress. 

If,
instead, Congress has left a gap for the administrative agency
to fill, we proceed to step two. 

. At step two, we
must uphold the administrative regulation unless it is “arbi-
trary, capricious, or manifestly contrary to the statute.” 

                        DISCUSSION

   Petitioners challenge two aspects of EPA’s approval of
Rule 4550 as being arbitrary, capricious, or not in accordance
with law. First, Petitioners claim that Rule 4550 does not
incorporate “all feasible measures,” as required by 42 U.S.C.
§ 7509(d)(2). Second, Petitioners assert that Rule 4550’s
menu of options for controlling agricultural PM-10 emissions
does not constitute BACM, as required by 42 U.S.C.
§ 7513a(b)(1)(B). We consider each of those arguments in
turn.

  A.   42 U.S.C. § 7509(d)(2)

   Section 7509 of the Act concerns the consequences of a
state’s failure to attain reduced emissions. The statute is con-
structed in such a way that, every time a state fails to meet a
deadline for its implementation plan or plan revision, the stat-
utory requirements become more stringent. For example, if
the EPA initially classifies an area as a moderate nonattain-
ment area, only the RACM standard applies. 42 U.S.C.
§ 7513a. If an area then fails to meet its deadline, the EPA
reclassifies that area as a serious nonattainment area, and the
more rigorous BACM standard applies. 

same area
again fails to meet its deadline, then its plan must provide for
attainment by achieving an annual reduction that is not less
                    LATINO ISSUES FORUM v. EPA               2753
than five percent of the amount of emissions as reported in the
most recent inventory prepared for the area. 

one year of the EPA Administrator’s publication of a
notice of failure to attain, the state must submit a revision to
the applicable SIP:

    [T]he revision shall include such additional measures
    as the Administrator may reasonably prescribe,
    including all measures that can be feasibly imple-
    mented in the area in light of technological achieva-
    bility, costs, and any nonair quality and other air
    quality-related health and environmental impacts.

   Petitioners argue that, under § 7509(d)(2), the District was
required to implement all feasible measures to control PM-10
emissions without delay, because the San Joaquin Valley had
failed to meet its attainment deadlines. Petitioners contend
that allowing agricultural operators to choose one control
option (among many) from each of a few categories fails to
meet the “all feasible measures” standard.

   The EPA responds with three separate arguments. First, the
EPA contends that § 7509(d)(2) does not apply to Rule 4550
because that statute applies only to the San Joaquin Valley
Plan as a whole. Second, the EPA asserts that Petitioners’
argument regarding § 7509(d)(2) is untimely because Peti-
tioners failed to raise their objection within 60 days of the
date of notice of approval of the San Joaquin Valley Plan.
Third, if § 7509(d)(2) does apply to Rule 4550 and if Petition-
ers raised their objection in time, the EPA argues that its inter-
pretation of § 7509(d)(2) as applied to Rule 4550 must be
upheld.

    1.   Section 7509(d)(2) applies to Rule 4550.

  The EPA argues that § 7509(d)(2) applies to the San Joa-
quin Valley Plan as a whole, but not to Rule 4550 on its own.
2754              LATINO ISSUES FORUM v. EPA
Specifically, the EPA asserts that it is in the context of a com-
prehensive attainment plan that the EPA prescribes Clean Air
Act planning obligations for a nonattainment area.

   [1] We disagree. Nothing in § 7509(d)(2) limits its applica-
tion to review of the plan in its entirety. To the contrary, the
statute plainly provides that § 7509 applies to “any implemen-
tation plan or plan revision required under this part . . . or
required in response to a finding of substantial inadequacy.”
42 U.S.C. § 7509(a) (emphases added). Rule 4550 was a
required revision to the District’s SIP. See 70 Fed. Reg. at
16,207 (“EPA is proposing to approve revisions to the [Dis-
trict’s] portion of the California [SIP]. These revisions con-
cern particulate matter emissions from agricultural
operations.”). Because Rule 4550 was a required revision to
the District’s SIP, and because § 7509 applies to any plan
revision, § 7509 of the Clean Air Act applies not only to the
San Joaquin Valley Plan as a whole, but also to Rule 4550
separately.

    2.   Petitioners timely      raised   their   objection   to
         § 7509(d)(2).

   Petitioners did not object to the EPA’s interpretation of
§ 7509(d)(2) during the notice-and-comment period preceding
the EPA’s adoption of the San Joaquin Valley Plan in 2004.
But, as we have explained, § 7509(d)(2) applies separately to
Rule 4550, which is a revision of the Plan. Accordingly, Peti-
tioners had to raise their objection in the notice-and-comment
period preceding the EPA’s approval of Rule 4550.

   The EPA received a letter from Petitioners, dated April 29,
2005, which asserted that Rule 4550 was defective because it
allowed agricultural operators to select only one control mea-
sure per category. 71 Fed. Reg. at 7683. Petitioners argued
that every available and feasible measure to control PM-10
must be mandated. 

did not cite
                 LATINO ISSUES FORUM v. EPA                2755
§ 7509(d)(2) as authority, the substance of its present argu-
ment plainly was raised.

   [2] This court “will refuse to consider contentions not pres-
ented before the administrative proceeding at the appropriate
time,” but waivers of arguments “are not designed to extin-
guish claims which, although not comprehensively or artfully
presented in the early stages of the administrative process, are
presented fully before the process ends.” Getty Oil Co. v.
Andrus, 

, 256 (9th Cir. 1979). Petitioners did
present their argument fully, even if not comprehensively or
artfully on account of failing to cite § 7509(d)(2). Therefore,
we hold that Petitioners’ argument regarding the applicability
of § 7509(d)(2) was not waived.

    3.   The EPA’s interpretation of § 7509(d)(2) is
         reasonable.

   The parties disagree about the interpretation of
§ 7509(d)(2). Petitioners argue that the EPA must include “all
feasible measures” in an implementation plan revision, mean-
ing that the plan revision must include all feasible measures;
in their view, the Administrator has discretion only in the
sense that he or she may decide what measures are technically
possible under statutory criteria. The structure of the Act,
Petitioners continue, supports that interpretation because Con-
gress demands more and more stringent control measures
when current requirements are insufficient to bring a particu-
lar area into attainment.

  The EPA offers an alternative reading of § 7509(d)(2). The
EPA argues that the section provides that submitted revisions
must contain additional measures, but that the only additional
measures required are those the Administrator reasonably
may choose to prescribe. The measures that the Administrator
may reasonably prescribe, the EPA asserts, include all mea-
sures that can be feasibly implemented in the area in light of
2756               LATINO ISSUES FORUM v. EPA
technological achievability, costs, and economic, health, and
environmental effects.

   [3] At the first step of the Chevron analysis, we conclude
that § 7509(d)(2) is ambiguous. The first clause states that a
plan revision “shall include such additional measures as the
Administrator may reasonably prescribe.” 42 U.S.C.
§ 7509(d)(2) (emphases added). Both of the parties’ interpre-
tations of § 7509(d)(2) are plausible and reasonable, one
emphasizing “shall” and the other emphasizing “may.”
Because § 7509(d)(2) is ambiguous and the EPA’s statutory
interpretation is reasonable, we hold that the EPA acted law-
fully by not requiring implementation of “all feasible mea-
sures” into Rule 4550.

  B.   42 U.S.C. § 7513a(b)(1)(B)

   [4] Petitioners next argue that Rule 4550’s menu of options
for controlling PM-10 emissions from agricultural sources
does not constitute the best available control measures. Sec-
tion 7513a(b)(1)(B) states that, for areas designated as “seri-
ous,” “[p]rovisions to assure that the best available control
measures for the control of PM-10 shall be implemented no
later than 4 years after the date the area is classified (or reclas-
sified) as a Serious Area.” The EPA set forth its definition of
BACM in its Addendum to the General Preamble of the Act:

    The BACM is the maximum degree of emissions
    reduction of PM-10 and PM-10 precursors from a
    source . . . which is determined on a case-by-case
    basis, taking into account energy, environmental,
    and economic impacts and other costs, to be achiev-
    able for such source through application of produc-
    tion processes and available methods, systems, and
    techniques for control of each such pollutant.

59 Fed. Reg. at 42,010 n.32 (emphasis added).
                      LATINO ISSUES FORUM v. EPA                         2757
      1.   History of Rule 4550 and its EPA approval.

   In a document titled “Revised Final Draft Staff Report,”
dated August 19, 2004, the District submitted its CMP Pro-
gram. The report states that more than half of all directly
emitted PM-10 emissions originate from agriculture-related
sources and that the purpose of the CMP Program is to limit
those emissions. Participation in the program is mandatory
unless a source falls below the exemption level. The program
is meant to function in the following way: Agricultural opera-
tors must select at least one CMP from each of the identified,
applicable CMP categories that is most appropriate to their oper-
ations.1 The selected CMPs then must be marked on the appli-
cations provided by the District to the agricultural operators.
The applications are submitted to the District for approval;
when approved by the District, the completed applications
constitute CMP Plans.

   Rule 4550 is part of the CMP Program, and its purpose “is
to limit fugitive dust emissions from agricultural operation
sites.” The rule applies only to larger farms and animal feed-
ing operations, but the District estimated that 90% of the har-
vested acres and more than 70% of the animal population in
the San Joaquin Valley would be covered.

  In developing Rule 4550, the District’s staff met with agri-
cultural representatives known as the AgTech Committee.
The AgTech Committee included representatives from the
  1
    The CMP categories are “Cropland,” “Poultry Operations,” “Dairy
Operations,” and “Feedlot Operations.” Each of those categories is divided
into four or five subcategories, and a number of CMPs are listed under
each subcategory. For example, to reduce PM-10 emissions from unpaved
roads in poultry operations, one CMP option is to minimize any and all
material that adheres to and agglomerates on all vehicles and equipment
from unpaved roads. Ways of accomplishing that goal include maintaining
a sufficient length of paved or graveled interior roads to allow mud and
dirt to drop off vehicles before exiting the site, or using a “grizzly” to dis-
lodge debris from the tires and undercarriages of vehicles leaving the site.
2758             LATINO ISSUES FORUM v. EPA
District, California Air Resources Board, California Cotton
Ginners Association, California Cotton Growers Association,
Nisei Farmers League, Almond Hullers and Processors Asso-
ciation, Natural Resource Conservation Services, EPA, and
local farm bureaus. Additionally, representatives from the
California Department of Food and Agriculture, Western
United Dairymen, and university researchers participated. The
District’s staff and the AgTech Committee organized various
stakeholder meetings over a two-year period to collect infor-
mation and discuss the CMP Program. They held two rounds
of public workshops to present the proposed rules and a draft
list of CMPs. Growers, public agencies, and other interested
parties provided comments. The District and the AgTech
Committee then held several focus group meetings to discuss
compliance costs and financial effects. The AgTech Commit-
tee developed a draft list of CMPs potentially suitable to agri-
cultural sources in the San Joaquin Valley nonattainment area.
The measures represented a wide array of potential CMPs and
were evaluated using available information on technological
feasibility, costs, energy, and environmental effects. The
AgTech Committee considered comments from various stake-
holders and conducted further evaluation itself. Eventually,
the draft CMP list was “refined to represent feasible, effective
and common sense practices for the nonattainment area[,]
which minimize potential negative impacts on local agricul-
ture.”

   In its “Technical Support Document for EPA’s Proposed
Rulemaking for the California [SIP],” the EPA evaluated Rule
4550 as submitted by the District. The EPA found that the
CMP list, which contains more than 100 practices that are
grouped into 18 CMP categories, “is more comprehensive
than any similar lists existing in other serious nonattainment
areas.” The EPA further noted that, when no feasible CMP
can be used from the list for a certain category, section 6.2 of
Rule 4550 allows an agricultural operator to select a substitute
CMP from another category. If an agricultural operator wants
to use a CMP not on the CMP list, it may do so after obtain-
                  LATINO ISSUES FORUM v. EPA                 2759
ing approval from the District. In order to be approved, the
alternative CMP must demonstrate that it achieves PM-10
emission reductions that are at least equivalent to the reduc-
tions expected from CMPs on the list.

   Rule 4550 requires that each agricultural operator imple-
ment at least one CMP for each applicable category but does
not require more than one CMP per category. The EPA rea-
sons that this flexibility gives agricultural sources a variety of
CMPs to select from in order to tailor PM-10 controls to their
individual circumstances without causing an unnecessary eco-
nomic burden. The EPA contends that a program requiring an
individual source to select one control method from a list, but
allowing the source to select which method, is most appropri-
ate for its situation. The EPA further emphasizes that giving
agricultural sources the discretion to choose from a range of
specified options is important for the agricultural sector
because of the variable nature of farming and the widely vary-
ing economic circumstances of farmers throughout the San
Joaquin Valley.

    After having evaluated the submitted rule and the CMP list,
the EPA concluded that Rule 4550 and the CMP list met the
BACM requirements of 42 U.S.C. § 7513a(b)(1)(B). The EPA
recommended approval of Rule 4550, and the District adopted
it.

    2.   The EPA followed its four-step process.

   [5] The EPA has created a four-step process to determine
BACM for a particular area: (1) developing an inventory of
the sources of PM-10 and PM-10 precursor emissions; (2)
evaluating, via modeling, the effect of PM-10 concentrations
of various sources to determine which are significant; (3)
evaluating the technological and economic feasibility of the
potential control measures; and (4) evaluating the costs and
energy and environmental impacts of potential BACM. 59
Fed. Reg. at 42,012 13. Those four steps emphasize the need
2760              LATINO ISSUES FORUM v. EPA
for flexibility and variability within particular plans. For
example, the first step, establishing an inventory of sources of
PM-10 and its precursors, specifies that the BACM “applica-
ble in a nonattainment area must be determined on a case-by-
case basis since the nature and extent of a nonattainment
problem may vary within the area and from one area to anoth-
er.” 

(emphasis added). The EPA further explains
that “[n]onattainment problems range from reasonably well-
defined areas of violation caused by a specific source or group
of sources to violations over relatively broad geographical
areas due predominantly to large numbers of small sources
widely-distributed over the area.” 

to the third
step, evaluating alternative control techniques, the EPA rec-
ognizes that the “technological feasibility of reducing emis-
sions from area sources depends on the ability to alter the
characteristics that affect emissions from the sources.” 

The characteristics to which the EPA refers “have to
do with the size or extent of the sources, their physical charac-
teristics[,] and the operating procedures.” 

argue that the EPA failed to follow its own
four-step process in determining BACM before approving
Rule 4550. We are not persuaded.

   [7] The administrative record shows that the District devel-
oped a detailed emissions inventory of source categories for
PM-10 and PM-10 precursors, as required by the first step, in
2004 as part of its revisions to the San Joaquin Valley SIP.
The EPA reviewed that inventory when it was submitted to it
as part of the total revisions to the SIP. 69 Fed. Reg. at
30,035. By approving all of the revisions to the SIP in 2004,
the EPA necessarily approved of the inventory of source cate-
gories submitted by the District. 

record also shows that the EPA reviewed the Dis-
trict’s de minimis analysis, as required by the second step,
when it proposed to approve the San Joaquin Valley SIP in
2004. 69 Fed. Reg. at 5,418. In that review, the EPA con-
                     LATINO ISSUES FORUM v. EPA                      2761
cluded “that the commitments and rules for the significant
source categories below meet the RACM/BACM require-
ments” of 42 U.S.C. § 7513a(b)(1)(B). 

third step for determining BACM is the evaluation
of the technological and economic feasibility of the control
measures. 59 Fed. Reg. at 42,012. The record demonstrates
that the District, together with the AgTech Committee, con-
ducted a thorough process in developing the CMP Program,
in which the feasibility of potential control measures was
evaluated. Further, recognizing that new practices will
become available with the advent of technology, the District
built into the CMP Program a means for upgrading the CMP
list as necessary. The District has committed to review the
CMP list every three years. The District’s staff stated in 2004
that it is committed to using the best available research and
to continue to work with the EPA to ensure that thorough
evaluations and assessments of possible new practices will be
conducted. The EPA noted the possibility of new practices in
its approval of Rule 4550, stating that BACM might change
over time “to a progressively tighter or more ambitious pro-
gram at later dates.”

   [10] The fourth and final step in determining BACM is to
evaluate the economic feasibility of implementing the control
measures. 59 Fed. Reg. at 42,013. The record contains
detailed analyses of the CMPs and an assessment of the costs,
feasibility, and effects associated with them. 71 Fed. Reg. at
7,685. Those analyses were included in the Staff Report that
the EPA reviewed. 70 Fed. Reg. at 16,208. The District evalu-
ated the costs of the CMP Plans to the agricultural industry in
its own Cost Effectiveness Analysis and Socioeconomic
Analysis. Additionally, the District’s Staff Report, on which
the EPA relied when it approved Rule 4550, includes a
detailed chart that lists the potential CMPs, describes each,
states the benefits of each, and sets forth examples.2 That Staff
  2
   The chart spans 20 pages and discusses the CMPs for croplands and
poultry, dairy, and feedlot operations. An illustrative CMP for cropland is
2762                 LATINO ISSUES FORUM v. EPA
Report provides the District’s rationale for selecting the vari-
ous options included in Rule 4550 as BACM.

   We have reviewed the EPA’s approval of a similar SIP for
compliance with 42 U.S.C. § 7513a(b)(1)(B). In Vigil, the
petitioners challenged the EPA’s approval of a SIP submitted
by Arizona to regulate a PM-10 serious nonattainment 

. The SIP contained a list of 34 potential con-
trol measures divided among three categories of farm activi-
ties. 

The regulation required commercial farmers
to implement at least one control measure per category. 

The petitioners in that case argued that the SIP did not
meet BACM requirements because the state ought to require
farmers to implement more than one control measure in each
category. 

that the “[p]etitioners’ argument would be
compelling if the [Clean Air] Act required a state to reduce
its emissions to the maximum extent possible, regardless of
cost.” 

EPA had defined BACM to mean the maxi-
mum degree of emissions reduction that would be determined
on a case-by-case basis. 

held that the EPA prop-
erly concluded that Arizona had provided for the maximum
degree of emissions reduction, all things considered, because
of the variability within the area and the impossibility that a

conservation irrigation. The chart lists its benefits as conserving water,
reducing weed population, reducing the need for tillage, and reducing soil
compaction. The chart issues the following directive as examples of meth-
ods for conservation irrigation: use of drip or buried line in crop produc-
tion; use of pressure bombs, water flow meters, or soil monitoring devices;
use of irrigation management consultants; and use of evapo-transpiration
factors. An example CMP for a feedlot operation is the addition of fibrous
material to working areas, which prevents dust disturbance. The chart lists
the following as possible methods: adding wood chips or other materials
to sorting alleys and high traffic areas to hold moisture and keep down
dust disturbance; putting damp manure solids right off the separator into
the heifer pens on a daily basis; and working the pens with a rotary har-
row.
                 LATINO ISSUES FORUM v. EPA                2763
single control measure would work equally well for all agri-
cultural operators. 

We also acknowledged that the
EPA had reviewed the process by which Arizona arrived at its
SIP, a process that included assembling representatives from
agriculture, state, and federal agencies and the University of
Arizona meeting over several years, holding public hearings,
and receiving public comments. 

We concluded that
the EPA’s approval of Arizona’s general permit rule as
BACM was not arbitrary and capricious because of “the
uncertainties involved in prescribing agricultural rules, the
measures that Arizona adopted, and the process by which Ari-
zona had arrived at its BMPs.” 

EPA’s approval process in this case was much
like the process used in Vigil. First, the District recognized
that Rule 4550 must provide flexibility to the agricultural
operator in choosing which control measures to use because
of the immense variability of agricultural sources. The EPA
noted the need for such flexibility in its evaluation. 71 Fed.
Reg. at 7,684; 69 Fed. Reg. at 30,014. Indeed, in Vigil, we
recognized the need for flexibility with regard to agricultural
sources of PM-10 emissions because “[a]gricultural sources
are unlike other stationary sources and unlike sources such as
automobiles that have common design features and may be
subjected to a common or uniform control 

. Due to the variability of weather and market condi-
tions, as well as the diversity among the agricultural operators
that fall under Rule 4550, it is reasonable to provide agricul-
tural operators the flexibility to choose whichever methods of
PM-10 reduction will be feasible for their individual proper-
ties.

   Second, the measures adopted here reasonably advance the
goal of reducing PM-10 emissions. The CMP list contains
more than 100 practices that are divided among 18 CMP cate-
gories. Each agricultural operator must adopt a minimum of
one CMP from every applicable category. Relying on the con-
clusions reached by the District and the AgTech Committee,
2764                LATINO ISSUES FORUM v. EPA
the EPA concluded that Rule 4550 and the CMP list provide
the maximum degree of PM-10 emission reductions achiev-
able from agricultural sources in the San Joaquin Valley.3

   Third, the process used by the District and approved by the
EPA is very similar to the one we accepted in Vigil: A com-
mittee composed of representatives from the government,
agricultural industry, and academia convened over a two-year
period, held public hearings, and received public comments.
Rule 4550 and the CMP list grew out of that collaborative
effort. There is no evidence in the record that the process was
improper in any way.

   [12] Petitioners attempt to distinguish Vigil by asserting
that we face a different issue than the one presented in Vigil:
whether the EPA demonstrated that the controls included in
the rule’s menu meet the stringency requirements of BACM.
Although the context is different, our inquiry into whether the
EPA properly followed the procedures set forth by the Act
remains the same. And, just as we held in Vigil, there is no
evidence here that the process which led to the creation and
adoption of Rule 4550 was improper.

      3.   Rule 4550 meets statutory requirements.

   Finally, Petitioners challenge the substance of Rule 4550.
Our role is only to ensure that the EPA made no “clear error
of judgment” that would render its action “arbitrary and capri-
cious.” 5 U.S.C. § 706(2)(a). Petitioners complain that “[t]he
record contains only a few examples of the actual control
effectiveness of the various options,” but there is no statutory
  3
   The EPA’s prediction turned out to be reasonable. The District’s Con-
servation Management Practices Program Report for 2005 found that,
from August 19, 2004, the date of the District’s adoption of Rule 4550,
through December 31, 2005, the District estimated that PM-10 emissions
reductions were 35.4 tons per day, which surpassed the CMP Program’s
commitment of PM-10 emissions reductions of 33.8 tons per day.
                 LATINO ISSUES FORUM v. EPA               2765
requirement that the District outline the actual control effec-
tiveness of every option in order to obtain the EPA’s
approval.

   Additionally, Petitioners complain that the CMP list lacks
sufficient detail in its description of the control measures.
This argument misconstrues the manner in which the CMP
Program is designed to work. Rule 4550 sets forth the process
for obtaining an approved CMP Plan from the District. The
CMP Plan itself contains the requirements with which each
particular source must comply. Section 6.1 of Rule 4550 con-
tains specific information that must be included in each appli-
cation for each agricultural site. Pursuant to sections 6.3 and
6.4, the application is then submitted, evaluated by the Dis-
trict, and either approved or disapproved as the applicant’s
enforceable CMP Plan. The application forms developed by
the District for this purpose are crop-specific and solicit the
details of how a chosen CMP is to be implemented.

   [13] Because the EPA made no clear error of judgment in
ruling that Rule 4550 complies with BACM, because the EPA
followed its regulatory process, and because that process was
consistent with one we approved in Vigil, we hold that the
EPA’s approval of Rule 4550 did not violate 42 U.S.C.
§ 7513a(b)(1)(B).

  PETITION DENIED.



THOMAS, Circuit Judge, concurring:

   I agree with the majority that the EPA’s cramped reading
of § 7509(d)(2) cannot be sustained, that § 7509(d)(2) applies
to Rule 4550, and that the petitioners did not waive their
objection to the EPA’s interpretation. I am also in accord that
the EPA’s interpretation of § 7509(d)(2)—that the statute
requires only those measures that the Administrator may rea-
2766              LATINO ISSUES FORUM v. EPA
sonably prescribe in light of technological achievability,
costs, and economic, health, and environmental effects—is
reasonable.

   Additionally, I concede that our decision in Vigil v. Leavitt,

(9th Cir. 2004), controls the question of whether
the “menu” approach to controlling emissions satisfies the
statutory requirement that an area designated as having a “se-
rious” air pollution problem must implement the best avail-
able control measures. Because I see no principled distinction
to be drawn between Vigil and this case, I concur in full with
the majority opinion.

   Nevertheless, if I were writing on a clean slate, uncon-
strained by Vigil, I would grant the petition. Although I see
no principled distinction between this case and Vigil, I do not
believe that the EPA’s Vigil-approved regime draws any
distinction—much less a principled one—between the “best
available control measures” to be used in areas of “serious”
pollution and the “reasonably available control measures”
required in areas of “moderate” pollution. If Vigil afforded
any analytical difference between the two, it is an illusion to
me now. As such, the EPA’s approval does not comply with
statutory requirements.

   The San Joaquin Valley is one of the nation’s top produc-
ing agricultural areas, sometimes referenced as “the nation’s
salad bowl.” But the abundance of produce comes at a price.
The Valley also hosts one of the nation’s worst particulate air
pollution problems, the bulk of which is created by agricul-
tural activity and propelled by nature. As even the casual trav-
eler driving down the Grapevine on the I-5 up to
Sacramento’s Highway 51 can attest, “you don’t need a
weatherman to know which way the wind blows.”1 Gusts
  1
  BOB DYLAN, Subterranean Homesick Blues, on BRINGING IT ALL BACK
HOME (Columbia Records 1965).
                  LATINO ISSUES FORUM v. EPA                 2767
“blowing down the backroads”2 carry dangerous particulate
emissions from the Valley to various locations in California,
from Yosemite to the Mojave Desert.

   Reacting to the Valley’s attainment failure, the EPA re-
designated it as a “serious non-attainment area,” and charged
the District with producing a pollution control plan that would
implement “best available control measures,” as opposed to
“reasonably available control measures.” However, rather
than proposing such a plan, the District suggested that indi-
vidual growers and producers choose which of a lengthy list
of dust control measures could be implemented with the least
cost, fuss or muss—leaving regulation to little more than a
simple twist of fate. Nothing in the plan prevents a grower
from choosing the least effective measures in each category,
even if it would be as feasible and less expensive to imple-
ment a more effective measure. The plan completely lacks
uniformity in controlling the manner in which particulate mat-
ter shall be released, even within the same agricultural cate-
gory or geographic region. Neighbors raising the same crop
are not regulated in the same way. Simply put, the plan is a
creature void of form. As such, it cannot comply with the stat-
utory directive that the region use “the best available control
measures.”

   In the EPA’s own provisional definitions of these terms, to
which we defer, economic impacts are properly considered in
determining best available control measures. Nevertheless,
“when comparing the terms ‘reasonable’ and ‘best’ as applied
to control measures, the word ‘best’ strongly implies that
there should be a greater emphasis on the merits of the mea-
sure or technology alone and less flexibility in considering
other factors.” Addendum to General Preamble, 59 Fed. Reg.
41,998, 42,011 (Aug. 16, 1994) (emphasis added).
  2
   BOB DYLAN, Idiot Wind, on BLOOD ON THE TRACKS (Columbia Records
1975).
2768              LATINO ISSUES FORUM v. EPA
   “Best” is a word that needs little elaboration, so it is one of
those tell tale signs that a concept is being drained of meaning
when elaborate rationalizations are posited. Here, the justifi-
cation for not requiring producers and growers to use the
“best available control measures” is that agriculture is compli-
cated. That observation, in some senses, is doubtless true. But
the subject at hand is dust control—not, for example, how
technologically best to remove sulphur from coal. The pollu-
tion control methods offered producers and growers as alter-
natives in the District’s plan are such measures as observing
the speed limit on dirt roads and cleaning out livestock pens
when the wind is known to be calm.

   Unquestionably, the notion of preventing soil erosion is not
new. Plato worried about “the richer and softer portions of the
soil having fallen away, and the mere skeletons of the land
being left.”3 In more modern times, the devastation of Okla-
homa’s dust bowl forged new methods of dust control in
farming. Likewise, techniques of proper livestock manage-
ment have been standardized for more than half a century.4 To
rationalize the lack of any basic dust control standards by
arguing that agriculture is just too complicated to regulate
defies reality and common sense.

   To be sure, if we were considering the District’s implemen-
tation of “reasonably available control measures,” applied in
areas of moderate pollution, I would have no quarrel. In many
ways, the District’s plan is quite laudable, particularly in these
hard times, when margins in our vital agricultural economy
are thin or non-existent, and many growers and producers are
facing potential insolvency. Given that grim reality, of which
I am acutely aware, I certainly cannot fault the District for
  3
   PLATO, CRITIAS (360 B.C.E.).
  4
   M.E. ENSMINGER, THE STOCKMAN’S HANDBOOK (Interstate Printers and
Publishers, 1955); FRANK B. MORRISON, FEEDS AND FEEDING (Morrison
Publishing Co., 21st ed. 1948).
                 LATINO ISSUES FORUM v. EPA              2769
attempting to minimize the financial impact of environmental
regulations, while committing to improve ambient air quality.

   Enticing as those considerations are, however, they are
quite beside the point to the legal analysis required of us.
When an area’s air pollution problem has graduated from
“moderate” to “serious,” Congress has mandated that the
“best available control measures” be employed. Perhaps that
standard doesn’t require growers to control every grain of
sand. But can we really say with a straight face that an amal-
gam of second, third, or tenth best available control measures
is, in the aggregate, the “best available control measure?” In
the San Joaquin Valley, the answer is blowing in the wind.