FILED
                                                      United States Court of Appeals
                                                              Tenth Circuit
                                 PUBLISH
                                                               May 23, 2017
               UNITED STATES COURT OF APPEALS
                                                            Elisabeth A. Shumaker
                      FOR THE TENTH CIRCUIT                     Clerk of Court
                     ____________________________________

ENERGY WEST MINING
COMPANY,

      Petitioner,

v.                                                    No. 16-9533

THE ESTATE OF MORRIS E.
BLACKBURN; PHYLLIS E.
BLACKBURN; DIRECTOR, OFFICE
OF WORKERS’ COMPENSATION
PROGRAMS, UNITED STATES
DEPARTMENT OF LABOR,

      Respondents.
                       _________________________________

                Petition for Review from an Order
                  of the Benefits Review Board
                    (BRB No. 2015-0290-BLA)
                       _________________________________

William S. Mattingly, Jackson Kelly PLLC, Lexington, Kentucky, for
Petitioner.

Evan B. Smith, Appalachian Citizens’ Law Center, Whitesburg, Kentucky,
for the Estate of Morris E. Blackburn, and Phyllis E. Blackburn,
Respondents.
                        _________________________________

Before KELLY, EBEL, and BACHARACH, Circuit Judges.
                  _________________________________

BACHARACH, Circuit Judge.
                  _________________________________
     Mr. Morris Blackburn worked as a coal miner for roughly twenty

years, continually exposing himself to dust in an Energy West coal mine.

He also smoked cigarettes and eventually developed a respiratory disease.

Based on this disease, Mr. Blackburn claimed benefits under the Black

Lung Benefits Act. 1 In response, Energy West contended that Mr.

Blackburn had caused his disease by smoking cigarettes. The United States

Department of Labor’s Benefits Review Board affirmed an award of

compensation, and Energy West petitions for review. We deny the petition,

concluding that the Board did not err in affirming the award.

I.   After a remand, an administrative law judge held that Energy
     West had failed to rebut the statutory presumption of an
     entitlement to benefits.

     This case began with Mr. Blackburn’s filing of a claim for statutory

benefits under the Black Lung Benefits Act, 30 U.S.C. §§ 901-945.

Statutory benefits are available to disabled coal miners who suffer from

various lung disorders as a result of their employment. In this case, the

parties agree that Mr. Blackburn was disabled from chronic obstructive

pulmonary disease, a type of lung disease, which in his case was




1
      Mr. Blackburn died while this appeal was pending. But if his claim is
valid, his surviving spouse would be entitled to benefits. See 30 U.S.C.
§ 932(l). After Mr. Blackburn died, we allowed the addition of Mr.
Blackburn’s widow as a respondent.


                                   2
characterized by emphysema. 2 The dispute is whether the disease was

caused by Mr. Blackburn’s work in a coal mine. One physician (Doctor

David James) answered “yes”; two other physicians (Doctors Robert

Farney and Peter Tuteur) answered “no.”

        In 2012, Administrative Law Judge Richard Malamphy denied

benefits. Judge Malamphy first found that Mr. Blackburn qualified for a

statutory presumption of an entitlement to benefits. But Judge Malamphy

determined that Energy West had rebutted the presumption by showing that

Mr. Blackburn’s lung disease had not arisen from his employment in a coal

mine.

        Mr. Blackburn appealed to the Benefits Review Board, which vacated

Judge Malamphy’s decision. In the Board’s view, Judge Malamphy had

simply summarized the evidence without explaining why he believed

Doctors Farney and Tuteur rather than Doctor James. The Board remanded

for Judge Malamphy to weigh the conflicting medical reports and provide a

reasoned decision.

        On remand, the case was reassigned to a different administrative law

judge (Judge Paul Johnson, Jr.). 3 Judge Johnson disagreed with Judge


2
     “COPD is a respiratory impairment characterized by chronic
bronchitis or emphysema and airflow obstruction.” Anderson v. Dir., Office
of Workers’ Comp. Programs, 

, 1104 n.3 (10th Cir. 2006).
3
        Judge Malamphy had retired by the time of the reassignment.


                                    3
Malamphy’s original decision, concluding that Energy West had not

rebutted the statutory presumption. For this conclusion, Judge Johnson

reasoned that Doctors Farney and Tuteur were not credible. On appeal, the

Board affirmed.

     Energy West petitions for review, arguing that the Board erred when

reviewing the decisions of both administrative law judges. For the first

decision, Energy West contends that Judge Malamphy provided an

adequate explanation. For the second decision, Energy West maintains that

Judge Johnson erroneously ruled beyond the scope of the remand, rendered

a decision unsupported by substantial evidence, drew his own medical

conclusions, treated the regulatory “preamble” as if it had the force of law,

failed to review the medical opinions in an even-handed way, and applied

the wrong legal standard.

     We deny Energy West’s petition. We agree with the Board that

          Judge Malamphy did not adequately explain his decision and

          Judge Johnson rendered a decision that was within the scope of
           the remand, was supported by substantial evidence, and did not
           improperly draw medical conclusions.

We also conclude that Judge Johnson did not treat the preamble as if it had

the force of law and did not improperly review the medical opinions. We

need not decide whether Judge Johnson applied the wrong legal standard

because any error would have been harmless.




                                   4
II.   Federal law creates a rebuttable presumption that disabled
      miners with at least 15 years of employment are entitled to
      benefits.

      Congress enacted the Black Lung Benefits Act to compensate coal

miners who become disabled from certain lung diseases (known

collectively as “pneumoconiosis”) that arose out of employment in a coal

mine. 30 U.S.C. § 901. To be entitled to benefits, a claimant must establish

four elements:

      1.    Disease (the miner suffers from pneumoconiosis),

      2.    Disease causation (the pneumoconiosis arose out of coal-mine
            employment),

      3.    Disability (the miner is totally disabled because of a
            respiratory or pulmonary impairment), and

      4.    Disability causation (the pneumoconiosis is a substantially
            contributing cause of the miner’s total disability).

Antelope Coal Co./Rio Tinto Energy Am. v. Goodin, 

, 1335

(10th Cir. 2014). 4

      There are two definitions of pneumoconiosis—“clinical” and “legal.”

20 C.F.R. § 718.201(a). This case involves legal pneumoconiosis, not

clinical pneumoconiosis. For legal pneumoconiosis, a miner must suffer

from “any chronic lung disease or impairment and its sequelae” that


4
      Our opinions have often combined the third and fourth elements into
a single third element. See, e.g., Blue Mountain Energy v. Dir., Office of
Workers’ Comp. Programs, 

, 1256 (10th Cir. 2015)
(providing a three-element test).


                                   5
“ar[ose] out of coal mine employment.” 

see Anderson

v. Dir., Office of Workers’ Comp. Programs, 

, 1104 (10th

Cir. 2006). Thus, for legal pneumoconiosis, claimants must satisfy both the

Disease and Disease causation elements. See 20 C.F.R. § 718.201(a)(2);

. In other words, the miner must suffer from

a chronic lung disease or impairment arising out of coal-mine employment.

      Ordinarily, claimants must prove each of the four elements. 

. But Mr. Blackburn had worked in a coal mine for at least

15 years. Thus, the Act softens his burden: The “15-year presumption”

provides that if Mr. Blackburn had established the Disability element, he

would have been entitled to a rebuttable presumption that the remaining

three elements (Disease, Disease causation, and Disability causation) were

also established. 5 See 30 U.S.C. § 921(c)(4); 20 C.F.R. § 718.305(b)-(c). 6




5
     Mr. Blackburn also cannot “establish entitlement under [20
C.F.R.] § 718.304 by means of chest x-ray evidence.” 20 C.F.R. §
718.305(b)(1)(ii) (requirement for the 15-year presumption).
6
      This presumption originally expired in 1982. See 30 U.S.C. §
921(c)(4) (2006) (“The provisions of this paragraph shall not apply with
respect to claims filed on or after the effective date of the Black Lung
Benefits Amendments of 1981.”); Black Lung Benefits Amendments of
1981, Pub. L. No. 97-119, tit. II, § 206, 95 Stat. 1635, 1645. In 2010,
Congress reinstated the presumption for claims filed after January 1, 2005,
that were pending on or after March 23, 2010. Patient Protection and
Affordable Care Act, Pub. L. No. 111-148, tit. I, § 1556, 124 Stat. 119,
260 (2010).


                                   6
The burden would then shift to Energy West to disprove one of these three

elements. See 30 U.S.C. § 921(c)(4); 20 C.F.R. § 718.305(d)(1).




     The parties agree that Mr. Blackburn satisfied his threshold burden,

triggering the presumption of Disease, Disease causation, and Disability

causation. Energy West tried to rebut the presumption by showing that Mr.

Blackburn never had legal pneumoconiosis because his lung disease had

not arisen out of his employment in a coal mine (Disease causation). See

20 C.F.R. § 718.305(d)(1)(i)(A) (indicating that the presumption may be

rebutted by establishing that the miner never had legal pneumoconiosis).

The Benefits Review Board affirmed Judge Johnson’s conclusion that

Energy West had not rebutted the presumption. On appeal, we consider the

correctness of the Board’s decision.




                                  7
III.   Standard of Review

       For questions of fact, we formally review the Board’s two decisions,

but focus on the decisions by the two administrative law judges. See

Antelope Coal Co./Rio Tinto Energy Am. v. Goodin, 

, 1341

n.13 (10th Cir. 2014). For questions of law, we engage in de novo review

of the Board’s decisions. 

IV.    Judge Malamphy did not adequately explain his decision.

       Energy West contends that the Board improperly concluded that

Judge Malamphy had not provided an adequate explanation for his denial

of benefits. This contention triggers de novo review. Gunderson v. U.S.

Dep’t of Labor, 

, 1021 (10th Cir. 2010). In conducting de

novo review, we agree with the Board that Judge Malamphy failed to

adequately explain the reasons for his conclusion. 7

       An agency’s adjudicative decision must be “‘accompanied by a clear

and satisfactory explication of the basis on which it rests.’” 

(quoting Barren Creek Coal Co. v. Witmer, 

, 356 (3d Cir.

1997)). This duty of explanation does not mandate “‘verbosity or

pedantry,’” but requires only that the administrative law judge provide an

7
     In 2016, when this case reached the Board for a second time, the
Board declined to disturb its earlier disposition. Blackburn v. Energy W.
Mining Co., BRB No. 15-0290 BLA, slip. op. at 4, 

, at
*2 (Ben. Rev. Bd. Apr. 26, 2016) (per curiam) (unpublished) (“Second
Board Decision”).




                                   8
explanation that allows us to discern the decision and the reasons for it. 

Mountain Coal Co. v. Mays, 

, 762 n.10 (4th

Cir. 1999)).

      In cases involving conflicting medical or scientific evidence, an

administrative law judge must “‘articulate a reason and provide support’”

to favor one opinion over another. 

v. Peabody Coal

Co., 

, 484 (7th Cir. 2007)). This requires more than a

“‘cursory statement’” that one expert’s opinion is more persuasive than

another’s. 

(quoting Barren 

). 8 Instead, an

administrative law judge must use his or her expertise to evaluate the

expert opinions. See 

      Judge Malamphy’s decision failed to provide an adequate

explanation. The relevant portion of his written opinion consisted almost

entirely of summaries of the medical evidence and block quotations from

the physicians’ reports. See Petitioner’s Opening Br., Attachment A at 6-




8
       In Energy West’s view, Gunderson stands only for the proposition
that “[t]he mere fact equally qualified experts gave conflicting testimony
does not authorize an [administrative law judge] to avoid the scientific
controversy by declaring a tie.” Petitioner’s Opening Br. at 18 (citing

). Energy West attempts to distinguish
Gunderson from the present case because Judge Malamphy did not declare
a tie. Notwithstanding this difference, Gunderson shows that an
administrative law judge, in resolving a scientific or medical controversy,
must explain why one expert’s opinion is more persuasive than another’s.


                                   9
15. Following the summaries and block quotations, Judge Malamphy stated

that Energy West had successfully rebutted the 15-year presumption:

            Drs. James, Farney, and Tuteur have given detailed
     reasoning for their opinions. Each party has relied on published
     treatises for their positions. [Mr. Blackburn’s] history of
     smoking is clearly more extensive than he acknowledged at the
     hearing.

           I find [Energy West] has rebutted the 15-year
     presumption by showing that [Mr. Blackburn] does not have
     pneumoconiosis. All of [Mr. Blackburn’s] X-ray readings and
     his CT-scan readings were negative for pneumoconiosis.
     Further, the medical opinion evidence does not support a
     finding of legal pneumoconiosis.

           Therefore, I find that evidence does not support a finding
     that [Mr. Blackburn] has pneumoconiosis.

This explanation references the medical-opinion evidence, Mr.

Blackburn’s smoking history, and his negative x-rays and CT-scans.

     Energy West makes two arguments for why Judge Malamphy’s

explanation was sufficient, pointing to (1) his selection of quotations and

(2) his observation that the x-rays and CT-scans were negative for

pneumoconiosis. These references do not substitute for an articulation of

why Judge Malamphy chose to believe Doctor Farney and Doctor Tuteur

over Doctor James.

     For the first argument, Energy West does not suggest that Judge

Malamphy expressly articulated his reasons for crediting the opinions of

Doctors Farney and Tuteur. Instead, Energy West contends that Judge

Malamphy’s rationale is discernible “when one reads between the lines of


                                  10
the decision” or analyzes the decision as a whole. See Petitioner’s Reply

Br. at 7.

      This argument fails as a matter of law. Like the Board, we are unable

to discern Judge Malamphy’s reasoning. Perhaps some readers may believe

that they can glean Judge Malamphy’s reasoning from his selection of

quotations. But these readers would ultimately only be guessing at Judge

Malamphy’s reasoning. This kind of guesswork should be unnecessary

because administrative law judges must articulate why they credit one

medical expert over another. 

. As a result, we

decline to look between the lines and into the mind of Judge Malamphy,

hoping to find a rationale where none has been articulated. 9

      Second, Energy West points to Judge Malamphy’s explanation that

“none of the chest x-rays or CT-scans reflect the existence of clinical

[pneumoconiosis, also known as] medical pneumoconiosis.” Petitioner’s

Opening Br. at 23. But the x-rays and CT-scans provide little help because

Mr. Blackburn relies on legal pneumoconiosis rather than on clinical

pneumoconiosis.




9
      The respondents contend that Judge Malamphy’s “long-form quotes”
constitute only his “summary of the facts, not his analysis of causation.”
Respondents’ Resp. Br. at 28. We need not consider this contention, for we
reject Energy West’s argument on other grounds.


                                  11
     At oral argument, Energy West shifted its theory, pointing to the

negative CT-scans to explain Judge Malamphy’s finding that Mr.

Blackburn did not have legal pneumoconiosis:

     The CT-scan demonstrated Dr. Farney[’s] [conclusion], as he
     explained, there was emphysema, he attributed the emphysema
     to cigarette smoking. So it supports his conclusion that legal
     pneumoconiosis was not present.

Oral Argument at 11:34-45. This argument is waived and unpersuasive.

The argument is waived because it was raised for the first time at oral

argument. See United States v. Burns, 

, 1223 n.2 (10th Cir.

2014). The argument is also unpersuasive. As quoted above, Energy West

points out that the CT-scans showed emphysema and Dr. Farney attributed

the emphysema to smoking rather than exposure to coal-mine dust. But

everyone agrees that Mr. Blackburn had emphysema; Judge Malamphy did

not say that the CT-scans had supported Dr. Farney’s conclusion about the

cause of the emphysema. As a result, we can only speculate about why

Judge Malamphy might have regarded the CT-scans as relevant to his

conclusion on legal pneumoconiosis.

                                   * * *

     Judge Malamphy did not articulate why he believed that Energy West

had rebutted the presumption of legal pneumoconiosis. Thus, the Board

correctly vacated Judge Malamphy’s decision.




                                  12
V.   The Board properly affirmed Judge Johnson’s decision.

     On remand, Judge Johnson decided to award benefits to Mr.

Blackburn. Petitioner’s Opening Br., Attachment C at 18. In reaching this

decision, Judge Johnson considered all of the medical opinions, including

those of Doctors Farney and Tuteur, who had attributed Mr. Blackburn’s

lung disease to smoking. Judge Johnson decided that the opinions of

Doctor Farney and Doctor Tuteur were not credible. As a result, Judge

Johnson concluded that Energy West had failed to rebut the presumption of

an entitlement to benefits. The Board upheld that decision.

     On appeal, Energy West presents six challenges to Judge Johnson’s

decision, arguing that Judge Johnson

     1.    ruled beyond the scope of the remand,

     2.    rendered a decision unsupported by substantial evidence,

     3.    improperly drew his own medical conclusions,

     4.    improperly relied on the “preamble” to the applicable
           regulations,

     5.    failed to compare the medical opinions in an even-handed way,
           and

     6.    applied the wrong legal standard.

     A.    Judge Johnson did not rule beyond the scope of the remand.

     Energy West contends that Judge Johnson’s ruling went beyond the

scope of the remand. We disagree.




                                 13
     After Judge Malamphy initially denied benefits, the Board vacated

the decision and remanded for the administrative law judge to provide an

adequate explanation. According to Energy West, the remand instructions

required Judge Johnson to provide an adequate explanation in Energy

West’s favor. 10 For this proposition, Energy West relies on the following

statement from the Board’s first decision:


10
     Energy West appears to reframe its argument between the filing of its
opening and reply briefs.

     In its opening brief, Energy West contended:

           The suggestion the case was remanded for an
     Administrative Law Judge to determine the weight to accord of
     these [medical] opinions and because the [administrative law
     judge] had discretion on remand to reconsider credibility
     findings, the prior determinations were not binding on rebuttal,
     is untenable. This is not what the 2013 Board found. The
     arguments claimants made to [Judge] Johnson had been made to
     the 2013 Board and it ruled there was no merit in the
     contention that the opinions of Drs. Farney and Tuteur were
     insufficient to support a finding of rebuttal of the presumption
     of total disability due to pneumoconiosis. Yet, those same
     arguments are now credited when [Judge] Johnson finds merit
     in the arguments that the opinions of Drs. Farney and Tuteur
     are insufficient to support a finding of rebuttal. The law-of-the
     case doctrine would not allow for such a bipolar interpretation
     of the same facts. The Board’s 2013 finding should have been
     applied.

Petitioner’s Opening Br. at 26-27 (citations omitted).

      Though this segment appears to challenge the administrative law
judge’s discretion to arrive at a different result on remand, Energy West
states in its reply brief that it “does not suggest” that the Board, when
reviewing Judge Malamphy’s decision, had made “an unrestricted holding


                                  14
     We find no merit . . . to [Mr. Blackburn’s] contention that the
     opinions of Drs. Farney and Tuteur are insufficient to support a
     finding of rebuttal, as both doctors opined that [Mr.
     Blackburn’s] respiratory impairment was not due, in whole or
     in part, to his coal mine employment.

Blackburn v. Energy W. Mining Co., BRB 12-0607 BLA, slip. op. at 5,

, at *2 (Ben. Rev. Bd. July 24, 2013) (per curiam)

(unpublished) (“First Board Decision”); see also Oral Arg. at 8:05-8:15

(counsel for Energy West stating that “[t]he instruction to the

[administrative law judge] was, ‘[y]ou can’t discredit them because they

did not say anything inappropriate’”).

     We disagree with Energy West’s interpretation of the Board’s

instructions. The Board was simply saying that the opinions by Doctor

Farney and Doctor Tuteur were not necessarily insufficient to rebut the

presumption—rather, that determination could be made only after the

administrative law judge determined which medical opinions were

persuasive:

     On remand, the administrative law judge must discuss and
     weigh all of the relevant evidence, resolve any scientific
     dispute on scientific grounds, and set forth the specific bases
     for his findings. The administrative law judge is reminded that

that the Board had reviewed, assessed, and found [Doctor Farney’s and
Doctor Tuteur’s] opinions sufficient to prove rebuttal.” Petitioner’s Reply
Br. at 16-17. Instead, Energy West insists that it is arguing only that the
first Board decision had rejected the idea that the medical opinions by
Doctors Farney and Tuteur were “invalid or contrary to the [regulatory]
Preamble and legally unable to establish rebuttal of the 15-year
presumption.” 

                                  15
      it is [Energy West]’s burden on rebuttal to [rebut the
      presumption].

First Board Decision at 5, 

, at *3; see Second Board

Decision at 5-6, 

, at *3. In other words, the Board was

just saying that the administrative law judge should determine whether the

employer had presented sufficient evidence to rebut the presumption, not

that the administrative law judge should decide in favor of the employer.

Otherwise the remand would have been pointless. 11

      Accordingly, we conclude that Judge Johnson did not deviate from

the remand instructions. 12

      B.    Judge Johnson’s decision was supported by substantial
            evidence.

      Energy West also contends that Judge Johnson’s decision was not

supported by substantial evidence. We disagree, concluding that the record

contains evidence that “‘a reasonable mind might accept as adequate to

support’” the administrative law judge’s conclusion. Energy W. Mining Co.


11
      The respondents also argue that (1) Judge Johnson “was not bound by
prior determinations of credibility” and (2) Judge Malamphy’s presence at
the hearing did not provide an advantage over Judge Johnson when
evaluating the experts’ credibility. Respondents’ Resp. Br. at 31 n.15. We
need not address these arguments.
12
      In arguing that Judge Johnson ruled beyond the scope of the remand,
Energy West assumes that the law-of-the-case doctrine applies to Board
decisions. For the sake of argument, we may assume that Energy West is
correct because this assumption would not affect the outcome.




                                 16
v. Oliver, 

, 1217 (10th Cir. 2009) (quoting Hansen v. Dir.,

Office of Workers Comp. Programs, 

, 368 (10th Cir. 1993)).

      Judge Johnson provided four reasons to question Dr. Farney’s

credibility 13 and one reason to question Dr. Tuteur’s credibility. 14


13
      Judge Johnson stated:

      [First,] th[e] study [relied upon by Dr. Farney], to the extent
      that it concluded there is a distinction between the contribution
      of cigarette smoking and that of coal-dust exposure to
      centrilobular emphysema is not actually addressed in the
      article, at least according to his summary. The article instead
      focused on the existence of clinical pneumoconiosis. [¶]

      Second, Dr. Farney’s reference to “the established pathogenesis
      and natural history of pulmonary diseases secondary to coal
      dust exposure” implies that centrilobular emphysema caused by
      coal-dust exposure is due to a different process from that
      caused by cigarette smoking. That position is contrary to the
      premise underlying the Black Lung regulations that coal dust
      exposure and cigarette smoking cause damage to the lungs by
      similar mechanisms. [¶]

      Third, Dr. Farney’s report is internally inconsistent in that he
      exhaustively discussed Mr. Blackburn’s smoking history, but
      then relied in part on the Rom study’s conclusion regarding
      non-smoking Utah coal miners. [¶]

      Fourth, Dr. Farney’s opinion fails to recognize that the
      Department of Labor has determined that coal dust and smoking
      have additive effects, and he did not discuss that possibility.

Petitioner’s Opening Br., Attachment C at 15-16.
14
      Judge Johnson stated:

      [Dr. Tuteur’s] attempts to show that Mr. Blackburn developed
      his disease from smoking, and not from coal-dust exposure,


                                    17
Energy West contends that Judge Johnson’s third and fourth reasons

for rejecting Dr. Farney’s opinion—an internal inconsistency and a

failure to consider the possibility of additive effects from coal-mine

dust and smoking—are unsupported by substantial evidence.

     First, Energy West challenges Judge Johnson’s conclusion that

Doctor Farney’s report was “internally inconsistent.” Petitioner’s Opening

Br., Attachment C at 16. This challenge involves Judge Johnson’s

reference to Doctor Farney’s discussion of a medical article. According to

Doctor Farney’s discussion, the article indicated that “non-cigarette

smoking” coal miners have a low risk of developing pneumoconiosis. See

id.; Respondents’ Supp. App’x at 112. Because Mr. Blackburn was a

smoker, Judge Johnson found it inconsistent for Doctor Farney to rely on

the article as a basis to conclude that Mr. Blackburn had a low risk of

developing legal pneumoconiosis. Petitioner’s Opening Br., Attachment C

at 16; Respondents’ Supp. App’x at 112.

     Energy West denies an inconsistency. Energy West appears to assume

that Mr. Blackburn’s smoking would not increase his risk of legal

pneumoconiosis. Petitioner’s Opening Br. at 35-36. Based on this apparent

assumption, Energy West suggests that Judge Johnson misunderstood how

     suffer from over-reliance on statistics and a lack              of
     individualized application of those data to Mr. Blackburn.

Petitioner’s Opening Br., Attachment C at 16.


                                  18
Mr. Blackburn’s situation had related to Dr. Farney’s conclusion from the

article. See 

supports Judge Johnson’s finding of an inconsistency.

Judge Johnson noted that according to the Department of Labor, medical

evidence shows that smoking can increase the risk of a miner developing

pneumoconiosis from coal-mine dust. Petitioner’s Opening Br., Attachment

C at 14-15. Based on the Department of Labor’s position, Judge Johnson

could reasonably find it inconsistent for Doctor Farney to conclude that

Mr. Blackburn had a low risk for legal pneumoconiosis just because the

risk was low for miners who had not smoked.

      Second, Energy West challenges Judge Johnson’s conclusion that

Doctor Farney did not consider the possibility that “coal dust and smoking

have additive effects.” Petitioner’s Opening Br., Attachment C at 16. This

challenge is two-fold: (1) that Judge Johnson erred in interpreting Doctor

Farney’s opinion and (2) that Judge Johnson misunderstood the preamble,

which states only that coal-mine dust and smoking can have additive

effects, not that they will always have additive effects. We reject both

challenges.

      Energy West first asserts that Doctor Farney considered the

possibility of additive effects. See Petitioner’s Opening Br. at 45-46 (“Dr.

Farney specifically recognizes the potential additive contribution of coal

dust, but negates any such contribution in Mr. Blackburn’s case based on a


                                  19
reasoned medical opinion.”). For this assertion, Energy West provides no

record citation.

      We conclude that substantial evidence supports Judge Johnson’s

finding. Doctor Farney stated that coal-mine dust can cause legal

pneumoconiosis “independent” of smoking, and he regarded this risk as

low. Respondents’ Supp. App’x at 111-12. Doctor Farney then concluded

that Mr. Blackburn’s risk of legal pneumoconiosis was the same as the risk

for a non-smoker. See 

Judge Johnson could reasonably conclude

that Doctor Farney had failed to consider the additive effects of coal-mine

dust and smoking.

      Energy West also asserts that the preamble states only that coal-mine

dust and smoking “can” have additive effects, not that they always “have”

additive effects. Petitioner’s Opening Br. at 45 (emphasis in original).

Again, Energy West provides no citation for this proposition.

      We conclude that Judge Johnson did not misunderstand the preamble.

The preamble favorably cites studies saying that coal-mine dust and

smoking have additive effects:

      [Lung function] decline occurs at a similar rate in smokers and
      nonsmokers, although the loss of lung function overall is
      greater in smokers, the two effects being additive. . . .

      . . . .

            . . . Smokers who mine have additive risk for developing
      significant obstruction. . . . [¶]



                                  20
           The message from the Marine study is unequivocal: Even
     in the absence of smoking, coal mine dust exposure is clearly
     associated with clinically significant airways obstruction and
     chronic bronchitis. The risk is additive with cigarette smoking.

     . . . .

          . . . “[T]he combined effects of coal mine dust and
     smoking on [lung function] appear to be additive.” . . .

           . . . [“I]t appears that the major damages caused by
     cigarette smoking is additive to the minor damage which can be
     attributed to coal dust.”

Regulations Implementing the Federal Coal Mine Health and Safety Act of

1969, as amended, 65 Fed. Reg. 79,920, 79,939-41 (Dec. 20, 2000)

(emphasis added) (citations omitted).

     This additive effect results in increased susceptibility to lung disease

for the group of coal miners who both smoked cigarettes and exposed

themselves to coal-mine dust.




                                  21
Addressing this group, Judge Johnson stated: “[T]he Department of Labor

has determined that coal dust and smoking have additive effects . . . .”

Petitioner’s Opening Br., Attachment C at 16. In our view, this statement

does not mischaracterize the preamble.

     We therefore reject Energy West’s factual challenges to Judge

Johnson’s criticisms regarding an inconsistency in Doctor Farney’s report

and his failure to consider the additive risk created by exposure to coal-

mine dust and smoking.

     C.    Judge Johnson did not interject his own medical opinions.

     Energy West also challenges Judge Johnson’s first criticism of

Doctor Farney’s opinion and the single criticism of Doctor Tuteur’s

opinion. According to Energy West, these criticisms show that Judge

Johnson interjected his own medical opinions. We disagree, concluding

that Judge Johnson properly weighed the medical opinions.

     First, Energy West challenges Judge Johnson’s criticism of Doctor

Farney’s reliance on a particular medical article. Dr. Farney had diagnosed

Mr. Blackburn’s lung disease as characterized by emphysema. Petitioner’s

Opening Br., Attachment C at 4 n.5. In light of this diagnosis, Judge

Johnson criticized Doctor Farney’s reliance on a medical article, stating

that “at least according to [Doctor Farney’s] summary,” the article had not

actually addressed the distinction between the contributions of smoking




                                  22
and coal-dust exposure on emphysema. 15 

see 

n.5. This

criticism leads Energy West to argue that Judge Johnson improperly acted

as a “medical expert.” Petitioner’s Opening Br. at 29. We disagree with

this characterization.

      Judge Johnson simply weighed the different medical opinions, as he

was required to do. Administrative law judges sometimes improperly

exceed their role by making their own medical diagnoses or using non-

scientific evidence to resolve a conflict between medical experts. Here,

though, Judge Johnson simply resolved a medical conflict on scientific

grounds. See Gunderson v. U.S. Dep’t of Labor, 

, 1023 (10th

Cir. 2010) (stating that an administrative law judge must rely on “scientific

grounds” “to resolve a scientific dispute”); 

(indicating that

an administrative law judge can make “scientific and technical judgments

within the scope of agency expertise” (quoting Wyoming v. United States,

, 1240 (10th Cir. 2002))); see also Dixie Fuel Co. v. Dir.,




15
      It is unclear whether Judge Johnson read this article or relied
solely on Doctor Farney’s summary of the article. But Energy West
has not argued that Judge Johnson failed to read the article or that he
mischaracterized the article. We therefore do not consider these
potential arguments.




                                  23
Office of Workers’ Comp. Programs, 

, 845-46 (6th Cir.

2016). 16

      Second, Energy West challenges Judge Johnson’s criticism of Doctor

Tuteur’s reliance on statistics. Doctor Tuteur concluded that Mr. Blackburn

probably did not have legal pneumoconiosis because only a small

percentage of coal miners suffer from legal pneumoconiosis. Petitioner’s

Opening Br., Attachment C at 16. Judge Johnson thought that this

conclusion relied too heavily on statistics rather than “individualized

application.” 

characterizes this criticism as Judge Johnson’s

interjection of his own medical opinion. We reject this characterization.

Judge Johnson simply analyzed Doctor Tuteur’s opinion based on a

scientific ground: the overreliance on statistics and lack of individualized

application. An administrative law judge can undertake this sort of

analysis. See, e.g., Antelope Coal Co./Rio Tinto Energy Am. v. Goodin, 743




16
      In Dixie Fuel Co., an administrative law judge concluded that a
medical report was not credible because the physician had relied partly on
medical articles that did not support the physician’s 

. The employer argued that the administrative law judge had
improperly “play[ed] expert” by examining the medical articles. 

The Sixth Circuit disagreed, explaining that the administrative law judge
had “merely fulfilled his role as fact-finder by evaluating the credibility of
[the physician’s] conclusions.” 

1331, 1345-46 (10th Cir. 2014); 17 see also Consol. Coal Co. v. Dir.,

Office of Workers Comp. Programs, 

, 735 (7th Cir. 2013)

(holding that the administrative law judge did not err by discrediting the

medical opinion of a doctor who had relied on general statistics because

the doctor had not related these statistics to the particular coal-mining

employee). We therefore reject Energy West’s argument.

      D.    Judge Johnson did not improperly rely on the “preamble”
            to the applicable regulations.

      Energy West also argues that Judge Johnson improperly relied on the

“preamble” to the applicable regulations. 18 According to Energy West,

Judge Johnson treated the preamble as the law even though the preamble

had not been subject to the Administrative Procedure Act’s notice-and-

comment requirements.


17
       In Goodin, the employer also presented testimony by medical
experts, who had opined that a coal miner’s chronic obstructive pulmonary
disease was statistically more likely to be caused by cigarettes or asthma
than by inhalation of coal-mine 

, 1345. The
administrative law judge rejected this reliance on statistical probabilities
because the medical experts had failed to account for the possibility that
this coal miner fell within the statistical minority of individuals
contracting chronic obstructive pulmonary disease from coal mining. 

We upheld this rationale as adequately supported by the record.

18
      The preamble to the 2001 amendments to the black lung regulations
provides the medical principles that underlie the Department of Labor’s
current regulations. See Regulations Implementing the Federal Coal Mine
Health and Safety Act of 1969, as amended, 65 Fed. Reg. 79,920, 79,920-
80,045 (Dec. 20, 2000).


                                   25
      We disagree based on our treatment of the issue in Blue Mountain

Energy v. Director, Office of Workers’ Compensation Programs, 

(10th Cir. 2015). There we distinguished between two distinct uses of

the preamble. In one, an administrative law judge uses the preamble to

“effect[] some sort of change in the law” or to create “a broadly-applicable

. This use of the preamble is improper. 

administrative law judge can consider the preamble as a tool to gauge an

expert’s credibility. See 

administrative law judge in Blue

Mountain had used the preamble only as a tool to weigh the causation

evidence for that case (rather than for a broader legal principle), we did

not fault the Board for affirming the administrative law judge’s decision.

      This dichotomy guides our consideration of Judge Johnson’s use of

the preamble. Energy West points to two of Judge Johnson’s statements:

(1) that Doctor Farney’s understanding of how coal-mine dust and cigarette

smoke affects the lungs was “contrary to the premise underlying the Black

Lung regulations,” and (2) that Doctor Farney had failed to acknowledge

the Department of Labor’s recognition of the additive effects of coal-mine

dust and smoking. Petitioner’s Opening Br., Attachment C at 16.

      We believe that Judge Johnson’s use of the preamble was proper. As

in Blue Mountain, the administrative law judge’s language refers to

analysis of the evidence “in this case.” Blue 

                                  26
(emphasis omitted). After discussing the premises underlying the preamble,

Judge Johnson indicated that

          he understood that all issues “must be resolved on a claim-by-
           claim basis” and

          he would “weigh the conflicting medical opinions in this case
           based on these principles.”

Petitioner’s Opening Br., Attachment C at 15.

     The disputed statements of Judge Johnson were nearly identical to

the administrative law judge’s language in Blue Mountain. There the

administrative law judge had said:

     Dr. Repsher’s opinion fails to address whether coal dust
     exposure and smoking could have been additive causes of
     Claimant’s lung disease, an etiology clearly adopted in the
     Preamble to the Regulations. . . . Dr. Parker specifically linked
     Claimant’s symptoms to the documented effects of coal mine
     exposure and cited to literature that has been approved by the
     Department in the Preamble.

Blue 

(emphasis modified) (ellipsis in original)

(citation omitted). Here too Judge Johnson indicated that he understood the

need to resolve each case on an individual basis. Thus, if use of the

preamble was permissible in Blue Mountain, the same must be true here.

     Energy West argues that this case differs from Blue Mountain

because the administrative law judge there made “limited references to the

preamble and looked to other portions of the medical opinions.”

Petitioner’s Opening Br. at 34. According to Energy West, Judge Johnson’s

use of the preamble was more expansive, using the preamble to conclude


                                  27
that “medical opinions which are based on the premise that coal dust-

related obstructive disease is completely distinct from smoking-related

disease are errant” and that “coal dust and smoking . . . always have

additive effects.” Petitioner’s Opening Br. at 33, 45 (emphasis omitted).

We disagree. Judge Johnson simply pointed out that Doctor Farney was

making unsupported assumptions that conflicted with the preamble. Had

Doctor Farney provided reasons for his assumptions, Judge Johnson would

have been bound to consider them. See Blue 

(“[A party] always ha[s] the ability to counter . . . the medical literature

cited in the preamble.”).

      We therefore conclude that Judge Johnson did not improperly treat

the preamble as the law. 19

      E.    The administrative law judge did not err when considering
            Dr. James’s opinion.

      Energy West contends that Judge Johnson was overly generous in his

consideration of Dr. James’s opinion. This contention reflects a

misunderstanding of how Judge Johnson applied Dr. James’s opinion.

Judge Johnson did describe Dr. James’s opinion as “well-documented and

19
      At oral argument, Energy West also argued that when Judge
Johnson had relied on the preamble, he “appl[ied] arguments never
made by the claimant.” Oral Argument at 8:20-35. If Energy West is
arguing that Judge Johnson erred in discussing the preamble without
a request by the claimant, this argument is waived by omission in
Energy West’s briefs. See United States v. Burns, 

,
1223 n.2 (10th Cir. 2014).


                                   28
well-reasoned.” Petitioner’s Opening Br., Attachment C at 16. But Judge

Johnson simply concluded that Dr. James’s opinion had not helped Energy

West to rebut the presumption. 

appears unassailable.

Energy West might disagree with Dr. James, but his opinion certainly did

not help Energy West to rebut the presumption.

      F.     If Judge Johnson had erroneously used the wrong legal
             standard, the error would have been harmless.

      Finally, Energy West argues that Judge Johnson applied an improper

legal standard that unfairly intensified Energy West’s burden. We need not

decide whether Judge Johnson erred because any such error would have

been harmless. See Antelope Coal Co./Rio Tinto Energy Am. v. Goodin, 

, 1348 (10th Cir. 2014) (concluding that “any alleged error was

harmless because Mr. Goodin would have prevailed even without the

[error]”).

      Energy West’s argument is straightforward. A federal regulation

allows Energy West to rebut the 15-year presumption by establishing that

Mr. Blackburn did not have legal pneumoconiosis or clinical

pneumoconiosis. 20 C.F.R. § 718.305(d)(1)(i). Only legal pneumoconiosis

is at issue here, for no one contends that Mr. Blackburn had clinical

pneumoconiosis. A different federal regulation defines legal

pneumoconiosis as a chronic lung disease or impairment “arising out of

coal mine employment.” 

The phrase “arising out of



                                  29
coal mine employment” “includes” any chronic disease or impairment

“significantly related to, or substantially aggravated by” dust from coal-

mine employment. 

(emphasis added). According to Energy

West, § 718.201(b) sets forth the relevant standard and Judge Johnson

deviated from this standard by requiring Energy West to completely “rule

out” any causal link between Mr. Blackburn’s exposure to coal-mine dust

and his lung disease.

     For the sake of argument, we can assume that Energy West is correct

regarding the standard and Judge Johnson’s failure to apply that standard.

Even with these assumptions, the alleged error would have been harmless

because Judge Johnson did not base his decision on Energy West’s failure

to rule out every connection between coal-mine dust and Mr. Blackburn’s

lung disease. Instead, Judge Johnson reasoned that Energy West’s evidence

was not credible.

     Energy West asserts that “[e]valuation under the correct legal

standard may have changed the credibility determinations.” Petitioner’s

Opening Br. at 28. We disagree. Judge Johnson rejected Doctor Farney’s

opinion because it had been unsupported by the referenced medical

literature, had contained an inconsistency, and had failed to address

important issues. And Judge Johnson rejected Doctor Tuteur’s opinion

because it had relied on statistics rather than on Mr. Blackburn as an




                                  30
individual. The rebuttal standard did not affect Judge Johnson’s analysis of

either doctor’s opinion.

     Energy West argues that a Board case, Minich v. Keystone Coal

Mining Corp., demonstrates that any error here was not harmless.

Petitioner’s Opening Br. at 28-29 (citing Minich v. Keystone Coal Mining

Corp., 25 Black Lung Rep. (Juris) 1-149 (Ben. Rev. Bd. 2015)). But

Minich did not need to address harmlessness because the administrative

law judge’s conclusion there had resulted directly from the administrative

law judge’s use of the wrong legal standard. There one doctor had found

that the effect of coal-mine dust was “insignificant,” and another doctor

had found that the effect was “not clinically significant.” Minich, 25 Black

Lung Rep. at 1-158. The administrative law judge decided in favor of the

claimant because the physicians could not exclude the possibility that

exposure to coal-mine dust had contributed to the claimant’s disability. 

to -158. The Board agreed with the employer’s criticism of the

rule-out standard and vacated the administrative law judge’s decision

awarding benefits to the coal miner. 

     In Minich, the Board never mentioned harmlessness or an issue

involving the credibility or persuasiveness of the doctors’ opinions. See 

considerations appeared unimportant because the

administrative law judge had taken the doctors’ opinions at face value.

Doing so, the administrative law judge had reasoned that the doctors’


                                  31
opinions would require an award of benefits under the rule-out standard.

See 

not the case here, for Judge Johnson did not take the medical

opinions at face value. Instead, Judge Johnson decided that the opinions of

Doctor Farney and Doctor Tuteur were not credible. In reaching this

decision, Judge Johnson had no reason to rely on the rule-out standard and

he didn’t. As a result, Minich bears little relevance and the alleged error

here was harmless.

VI.   Disposition

      We deny the petition for review.




                                  32