PUBLISH UNITED STATES CO URT OF APPEALS FOR THE TENTH CIRCUIT

____________________ ________________ ENERGY WEST MINING COMPANY, Petitioner,

v. THE ESTATE OF MORRIS E. BLACKBURN; PHYLLIS E. BLACKBURN; DIRECTOR, OFFICE OF WORKERS’ COMPENSATION PROGRAMS, UNITED STATES DEPARTMENT OF LABOR, Respondents. No. 16-9533

__________________ _______________ Petition for Review from an Order of the Benefits Review Board

(BRB No. 2015-0290-BLA)

__________________ _______________ William S. Mattingly, Jackson Kell y PLLC, Lexington, Kentucky, for Petitioner. Evan B. Smith, Appalach ian Citizens’ La w Center, Whitesburg, Kentucky, for the Estate of Morr is E. Blackburn, and Phyllis E. Blackburn, Respondents.

__________________ _______________ Before KELLY , EBEL , and BACHARACH , Circuit Judges.

__________________ _______________ BACHARACH , Circuit Judge.

__________________ _______________ FILED United States Court of Appeals Tenth Circuit 

### May 23, 2017
Elisabeth A. Shumaker Clerk of Court2 Mr. Morris Blackburn wo rked as a coal mine r for roughly twenty years, continually exposing himself to dust in an Energy West coal mine. He also smoked cigarettes and eventua lly developed a respiratory disease. Based on this disease, Mr. Blackburn claimed benefits under the Black Lung Benefits Act. 1 In response, Energy We st contended that Mr. Blackburn had caused his disease by smoking ciga rettes. 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 Bo ard did not err in a ffirming the award.
I. After a remand, an administrati ve law judge he ld 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 Bene fits Act, 30 U.S. C. §§ 901-945. Statutory benefits are available to di sabled 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 appe al 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.3 characterized by emphysema. 2 The dispute is whet her the disease was caused by Mr. Blackbu rn’s work in a coal mine. One physician (Doctor David James) answered “yes”; two other physicians (D octors Robert Farney and Peter Tuteur) answered “no.” In 2012, Administrative Law J udge Richard Malamphy denied benefits. Judge Malamphy first found that Mr. Blackburn qual ified for a statutory presumption of an entitleme nt to benefits. But Judge Malamphy determined that Energy We st had rebutted the presumption by showing that Mr. Blackburn’s lung dise ase had not arisen from his employment in a coal mine. Mr. Blackburn appealed to the Benefits Review Board, which vacated Judge Malamphy’s decisi on. In the Board’s view , Judge Malamphy had simply summarized the evidence wi thout explaining why he believed Doctors Farney and Tuteur rather than Doctor James. Th e Board remanded for Judge Malamphy to weigh the conflicting me dical 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 disa greed with Judge

2 “COPD is a respiratory impair ment characteriz ed by chronic bronchitis or emphysema an d airflow obstruction.” Anderson v. Dir., Office of Workers’ Comp. Programs , 455 F.3d 1102, 1104 n. 3 (10th Cir. 2006).

3 Judge Malamphy had retired by the time of the reassignment.4 Malamphy’s original decision, conc luding that Energy West had not rebutted the statutory presumption. For this conclusion, Judge Johnson reasoned that Doctors Farn ey and Tuteur were not credible. On appeal, the Board affirmed. Energy West petitions for review, ar guing that the Bo ard erred when reviewing the decisi ons of both administrative law j udges. For the first decision, Energy West contends th at Judge Malamphy provided an adequate explanation. Fo r the second deci sion, Energy West maintains that Judge Johnson erroneously ruled beyond the scope of the re mand, rendered a decision unsuppo rted by substant ial 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 adequate ly explain his decision and

 Judge Johnson rendered a decision that was within the scope of the remand, was support ed by substantial ev idence, and did not improperly draw medical conclusions. We also conclude that J udge Johnson did not treat the preamble as if it had the force of law and did not improper ly review the medi cal opinions. We need not decide whether Judge Johnson applied th e wrong legal standard because any error would have been harmless.5 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 di sabled from certain lung diseases (known collectively as “pneumoconiosis”) that arose out of employ ment 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 ar ose out of coal-mine employment),
3. Disability (the miner is totally disabled because of a respiratory or pulmon ary impairment), and
4. Disability causation (the pneumoconiosis is a substantially contributing cause of the miner’s total disability). Antelope Coal Co./Rio Ti nto Energy Am . v. Goodin , 743 F.3d 1331, 1335 (10th Cir. 2014). 4
There are two definition s of pneumoconiosis—“cl inical” 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 , 805 F.3d 1254, 1256 (10th Cir. 2015) (providing a three-element test).6 “ar[ose] out of coal mine employment.” Id. § 718.201(a)(2); see Anderson v. Dir., Office of Workers’ Comp. Programs , 455 F.3d 1102, 1104 (10th Cir. 2006). Thus, for lega l pneumoconiosis, claimant s must satisfy both the
Disease and Disease causation elements. See 20 C.F.R. § 718.201(a)(2); Anderson , 455 F.3d at 1105-07. 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. Goodin , 743 F.3d at 1335. 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. Bl ackburn had esta blished 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 al so cannot “establish entitlement under [20 C.F.R.] § 718.304 by mean s of chest x-ray evid ence.” 20 C.F.R. § 718.305(b)(1)(ii) (requirement for the 15-year presumption).

6 This presumption orig inally expired in 1982. See 30 U.S.C. § 921(c)(4) (2006) (“Th e provisions of this para graph shall not apply with respect to claims filed on or after th e effective date of the Black Lung Benefits Amendments of 1981.”); Bl ack Lung Benefits Amendments of 1981, Pub. L. No. 97- 119, tit. II, § 206, 95 Stat. 1635, 1645. In 2010, Congress reinstated the pr esumption for claims file d after January 1, 2005, that were pending on or after March 23, 2010. Patient Protection and Affordable Care Act, Pu b. L. No. 111-148 , tit. I, § 1556 , 124 Stat. 119, 260 (2010).7 The burden would then shif t to Energy West to disp rove 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 s howing that Mr. Blackburn never had legal pneumoconiosis becau se his lung disease had not arisen out of his empl oyment 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 Bo ard affirmed Judge John son’s conclusion that Energy West had not rebutted the presum ption. On appeal, we consider the correctness of the Bo ard’s decision.8 III. Standard of Review For questions of fact, we formally review the Board’s two decisions, but focus on the decisions by the two ad ministrative law judges. See Antelope Coal Co./Rio Ti nto Energy Am . v. Goodin , 743 F.3d 1331, 1341 n.13 (10th Cir. 2014 ). For questions of law, we engage in de novo review of the Board’s decisions. Id. at 1341. IV. Judge Malamphy did not adequa tely explain his decision. Energy West contends that the Bo ard improperly concluded that Judge Malamphy had not pr ovided an adequate explanation for his denial of benefits. This contentio n triggers de novo review. Gunderson v. U.S. Dep’t of Labor , 601 F.3d 1013, 1021 (10th Cir. 2010). In conducting de novo review, we agree wi th the Board th at Judge Malamphy failed to adequately explain the r easons for his conclusion. 7 An agency’s adjudicative decision mu st be “‘accompanied by a clear and satisfactory explication of the basis on which it rests.’” Id . at 1022 (quoting Barren Creek Coal Co. v. Witmer , 111 F.3d 352, 356 (3d Cir. 1997)). This duty of explanation does not ma ndate “‘verbosity or pedantry,’” but requires only that th e administrative la w judge provide an

7 In 2016, when this case reached the Board fo r 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, 2016 WL 8260661, at *2 (Ben. Rev. Bd . Apr. 26, 2016) (p er curiam) (unpubli shed) (“Second Board Decision”).9 explanation that allows us to discer n the decision and the reasons for it. Id. (quoting Piney Mountain Coal Co. v. Mays , 176 F.3d 753, 762 n.10 (4th Cir. 1999)). In cases involving conflicting medi cal or scientific evidence, an administrative law judge mu st “‘articulate a reason and provide support’” to favor one opinion over another. Id. (quoting Stalcup v. Peabody Coal
Co. , 477 F.3d 482, 484 (7th Cir. 2007)). This requires more than a “‘cursory statement’” that one expert’s opinion is more persuasive than another’s. Id. at 1023 (quoting Barren Creek , 111 F.3d at 354). 8 Instead, an administrative law judge mu st use his or her expertise to evaluate the expert opinions. See id. at 1022-23. Judge Malamphy’s d ecision failed to pr ovide an adequate explanation. The relevant portion of his written opinion consisted almost entirely of summaries of the medi cal evidence and bl ock 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 qualif ied experts gave conflicting testimony does not authorize an [a dministrative law judge] to avoid the scientific controversy by declaring a tie.” Petiti oner’s Opening Br. at 18 (citing Gunderson , 601 F.3d at 1024). Energy West attemp ts to distinguish Gunderson from the present case because Judge Malam phy 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.10 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 op inions. Each party ha s relied on published treatises for their positions. [Mr. Blackburn’s] history of smoking is clearly mo re extensive than he acknowledged at the hearing. I find [Energy West] ha s rebutted the 15-year presumption by showing that [M r. Blackburn] do es not have pneumoconiosis. All of [Mr. Bl ackburn’s] X-ray readings and his CT-scan readings were negative for pneumoconiosis. Further, the medical opinion evidence do es not support a finding of legal pneumoconiosis. Therefore, I find that eviden ce does not suppo rt a finding that [Mr. Blackburn] has pneumoconiosis. Id. at 15. This explanatio n references the medical-opinion evidence, Mr. Blackburn’s smoking histor y, 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 sel ection of quotations and (2) his observation that the x-rays and CT-sca ns were negative for pneumoconiosis. These references do no t substitute for an articulation of why Judge Malamphy chose to believe Doctor Farn ey and Doctor Tuteur
over Doctor James. For the first argument, Energy West does not suggest th at Judge Malamphy expressly articulated his r easons 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 of11 the decision” or analyzes the decision as a whole. See Petitioner’s Reply
Br. at 7. This argument fails as a matter of la w. Like the Board, we are unable to discern Judge Malamphy ’s reasoning. Perhaps so me readers may believe that they can glean J udge Malamphy’s reasonin g from his selection of quotations. But these read ers would ultimately only be guessing at Judge Malamphy’s reasoning. This kind of guesswork should be unnecessary because administrative law judges mu st articulate why they credit one medical expert over another. Gunderson , 601 F.3d at 1022. As a result, we decline to look between the lines and into the mi nd of Judge Malamphy, hoping to find a rationale wher e none has been articulated. 9 Second, Energy West points to Judge Malam phy’s explanation that “none of the chest x-rays or CT-scans reflect the existence of clinical [pneumoconiosis, also known as] medi cal 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 cont end that Judge Malamphy ’s “long-form quotes” constitute only his “summary of the f acts, not his analysis of causation.” Respondents’ Resp. Br. at 28 . We need not consider this contenti on, for we reject Energy West’s ar gument on other grounds.12 At oral argument, Ener gy West shifted its theo ry, pointing to the negative CT-scans to explain Judg e Malamphy’s fi nding 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 s upports his conclusion that legal pneumoconiosis was not present. Oral Argument at 11:34- 45. This argument is waived and unpersuasive. The argument is waived be cause it was raised for the first time at oral argument. See United States v. Burns , 775 F.3d 1221, 1223 n.2 (10th Cir. 2014). The argument is al so unpersuasive. As quote d above, Energy West points out that the CT-s cans showed emphysema and Dr. Farney attributed the emphysema to smoking rather than exposure to co al-mine dust. But everyone agrees that Mr . Blackburn had emphysema; Judge Malamphy did not say that the CT-scans had supported Dr . Farney’s conc lusion about the

cause of the emphysema. As a result, we can only spec ulate 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.13 V. The Board properly affirmed Judge Johnson’s decision. On remand, Judge Johnson decide d to award benefits to Mr. Blackburn. Petitioner’s Op ening Br., Attachment C at 18. In reaching this decision, Judge Johnson co nsidered 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 we re not credible. As a result, Judge Johnson concluded that En ergy West had failed to rebut the presumption of an entitlement to benefits. Th e Board upheld that decision. On appeal, Energy West presents six challeng es to Judge Johnson’s decision, arguing th at Judge Johnson
1. ruled beyond the scop e 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 opi nions in an even-handed way, and
6. applied the wrong legal standard. A. Judge Johnson did not rule be yond the scope of the remand. Energy West contends that Judg e Johnson’s rulin g went beyond the scope of the remand. We disagree.14 After Judge Malamphy in itially denied benef its, the Board vacated the decision and remanded for the administrative law judge to provide an adequate explanation. A ccording to Energy West, the remand instructions required Judge Johnson to prov ide an adequate explanation in Energy West’s favor

. 10 For this proposition, Energy We st relies on the following statement from the Bo ard’s first decision:

10 Energy West appears to reframe its argument between th e filing of its opening and reply briefs. In its opening brief, Energy West contended: The suggestion the cas e was remanded for an Administrative Law Judge to dete rmine the weight to accord of these [medical] opinions and b ecause the [admin istrative law judge] had discretion on remand to reconsider credibility findings, the prior determinations were not bindi ng on rebuttal, is untenable. This is not wh at the 2013 Boar d found. The arguments claimants made to [Judge] Johnson had been made to the 2013 Board and it ruled th ere 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 s upport a finding of rebu ttal. 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 ad ministrative law judge’s discretion to arri ve 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 unr estricted holding15 We find no merit . . . to [Mr. Blackburn’s] conten tion that the opinions of Drs. Farn ey and Tuteur are insu fficient to support a finding of rebuttal, as both doctors opined that [Mr. Blackburn’s] respiratory impairme nt 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, 2013 WL 4407026, 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 wa s 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 judg e must discuss and weigh all of the relevant evidence, resolve any scientific dispute on scientific grounds, and set fort h the specific bases for his findings. The administrative law j udge is reminded that
that the Board had revi ewed, assessed, and found [Doctor Farney’s and Doctor Tuteur’s] opinions sufficient to prove rebu ttal.” Petitioner’s Reply Br. at 16-17. Instead, En ergy 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 cont rary to the [regulatory] Preamble and legally unable to establish rebuttal of the 15-year presumption.” Id. at 17.16 it is [Energy West]’s burden on rebuttal to [rebut the presumption]. First Board Decision at 5, 2013 WL 4407026, at *3; see Second Board Decision at 5-6, 2016 WL 8260661, at *3. In other words, the Board was just saying that the administrative law judge should de termine whether the employer had presented su fficient evidence to rebu t the presumption, not that the administrative la w judge should de cide 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 wa s supported by substantial evidence. Energy West also contends that Judge Johnson’s de cision was not supported by substantial ev idence. We disagree, conc luding 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” an d (2) Judge Malamphy ’s presence at the hearing did not provide an ad vantage over Judg e Johnson when evaluating the experts’ cr edibility. Respondents’ Re sp. Br. at 31 n.15. We need not address these arguments.

12 In arguing that Judg e Johnson ruled beyond th e scope of the remand, Energy West assumes that the law-of-t he-case doctrine applies to Board decisions. For the sake of argument, we may a ssume that Ener gy West is correct because this assumption would not affect the outcome.17 v. Oliver , 555 F.3d 1211, 1217 (10th Cir. 2009) (quoting Hansen v. Dir., Office of Workers Comp. Programs , 984 F.2d 364, 368 (10th Cir. 1993)). Judge Johnson provided four reas ons to question Dr. Farney’s credibility 13 and one reason to questi on Dr. Tuteur’s credibility. 14

13 Judge Johnson stated: [First,] th[e] study [re lied upon by Dr. Farn ey], to th e 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 re ference to “the established pathogenesis and natural history of pulmonar y diseases secondary to coal dust exposure” implies that cen trilobular emphysema caused by coal-dust exposure is due to a different process from that caused by cigarette sm oking. That position is contrary to the premise underlying the Black Lung regulations th at coal dust exposure and cigarette smoking cause damage to the lungs by similar mechanisms. [¶] Third, Dr. Farney’s report is inte rnally inconsiste nt in that he exhaustively discu ssed 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 determin ed 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] attemp ts to show that Mr . Blackburn developed his disease from smoking, and not from coal-dust exposure,18 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 subs tantial evidence. First, Energy West ch allenges Judge Johnso n’s conclusion that Doctor Farney’s report was “internally inconsiste nt.” Petitioner’s Opening Br., Attachment C at 16. This challenge involves Judge Johnson’s reference to Doctor Farney ’s discussion of a medica l article. According to Doctor Farney’s discu ssion, the article indicat ed that “non-cigarette smoking” coal miners have a low ri sk of developing pneumoconiosis. See id .; Respondents’ Supp. App’x at 112. Because Mr. Blackburn was a smoker, Judge Johnson found it inconsistent for Doct or Farney to rely on the article as a basis to conclude th at Mr. Blackburn ha d 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 inconsistenc y. Energy West appears to assume that Mr. Blackburn’s smok ing 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 J ohnson misunderstood how
suffer from over-reliance on statistics and a lack of individualized appli cation of those data to Mr. Blackburn. Petitioner’s Opening Br ., Attachment C at 16.19 Mr. Blackburn’s situation had related to Dr. Farney’s conclusion from the article. See id. The record s upports Judge Johnso n’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 ri sk for legal pneumoconi osis just because the risk was low for miners who had not smoked. Second, Energy West ch allenges Judge Johnson’s conclusion that Doctor Farney did not cons ider the possibility that “coal dust and smoking have additive effects.” Pe titioner’s Opening Br., At tachment C at 16. This challenge is two-fo ld: (1) that Judge Johnson erred in in terpreting Doctor Farney’s opinion and (2) that Judge Johnson mis understood the preamble, which states only that coal-mine dust and smoking can have additive effects, not that they will always ha ve 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 po tential additive contribution of coal dust, but negates any such contribution in Mr. Bl ackburn’s case based on a20 reasoned medical opinion.”) . For this assertion, En ergy West pr ovides no record citation. We conclude that substantial ev idence supports Judge Johnson’s finding. Doctor Farney stated that coal-mine dust can cause legal pneumoconiosis “independe nt” of smoking, and he regarded this risk as low. Respondents’ Supp. App’x at 111-1 2. Doctor Farney then concluded that Mr. Blackburn’s risk of legal pneumoconiosis wa s the same as the risk for a non-smoker. See id. at 112. Judge Johnson co uld reasonably conclude that Doctor Farney had failed to consid er the additive effects of coal-mine dust and smoking. Energy West also asserts that the pr eamble states only that coal-mine dust and smoking “ can ” have additive effects, not that they always “ have ” additive effects. Petitione r’s Opening Br. at 45 (e mphasis in original). Again, Energy West pr ovides no citation fo r this proposition. We conclude that Judg e Johnson did not misund erstand the preamble. The preamble favorably cites stud ies saying that coal-mine dust and smoking have additive effects: [Lung function] decline occurs at a similar rate in smokers and nonsmokers, although th e loss of lung func tion overall is greater in smokers, the two effects being additive. . . .

. . . . . . . Smokers who mine have additive risk for developing significant obstruct ion. . . . [¶]21 The message from th e Marine study is unequivocal: Even in the absence of smok ing, coal mine dust exposure is clearly associated with clin ically significant airways obstruction and chronic bronch itis. The risk is additive with cigarette smoking.

. . . . . . . “[T]he combined effect s 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 resu lts in increased susceptib ility to lung disease for the group of coal miners who both smoked cigarettes and exposed themselves to coal-mine dust.22 Addressing this group, J udge Johnson stated: “[T]he Department of Labor has determined that coal dust and smoking have ad ditive 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 challe nges to Judge Johnson’s criticisms regarding an incons istency in Doctor Farney’s report and his failure to consider the additive risk created by exposure to coalmine dust and smoking. C. Judge Johnson did not interject his own medical opinions. Energy West also challenges Judg e Johnson’s first criticism of Doctor Farney’s opinion and the single criticis m 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 ch allenges Judge Johnson’ s criticism of Doctor Farney’s reliance on a particular medical article. Dr. Farney had diagnosed Mr. Blackburn’s lung dise ase 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 Fa rney’s] summary,” th e article had not actually addressed the distinction be tween the contribu tions of smoking23 and coal-dust exposure on emphysema. 15 Id . at 15-16; see id. at 4 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 di fferent medical op inions, as he was required to do. Administrative law judges some times improperly exceed their role by ma king their own medical diagnoses or using nonscientific evidence to resolve a conflict between medical experts. Here, though, Judge Johnson simp ly resolved a medical conflict on scientific grounds. See Gunderson v. U. S. Dep’t of Labor , 601 F.3d 1013, 1023 (10th Cir. 2010) (stating that an administrative law judge must rely on “scientific grounds” “to resolve a scientific dispute”); id. at 1022-23 (indicating that an administrative law j udge can make “scientific and technical judgments within the scope of agen cy expertise” (quoting Wyoming v. United States , 279 F.3d 1214, 1240 ( 10th Cir. 2002))); see also Dixie Fuel Co. v. Dir.,

15 It is unclear whet her Judge Johnson read this article or relied solely on Doctor Farn ey’s summary of the ar ticle. But Energy West has not argued that Judg e Johnson failed to read the article or that he mischaracterized the article. We therefore do not consider these potential arguments.24 Office of Workers’ Comp. Programs , 820 F.3d 833, 845- 46 (6th Cir. 2016). 16 Second, Energy West cha llenges Judge Johnson’ s criticism of Doctor Tuteur’s reliance on sta tistics. Doctor Tuteur co ncluded that Mr. Blackburn probably did not have legal pneumoconiosis because only a small percentage of coal miners suffer fr om legal pneumoconi osis. Petitioner’s Opening Br., Attachment C at 16. Judge Johnson t hought that this conclusion relied too heavily on stat istics rather than “individualized application.” Id. Energy West characterizes this criticism as Judge Johnson’s interjection of his own medical opinion. We reject this characterization. Judge Johnson simply analyzed Doct or Tuteur’s opinion based on a scientific ground: the overre liance on statistics and la ck of individualized application. An administrative law judge can undertake this sort of analysis. See, e.g. , Antelope Coal Co./Rio Ti nto Energy Am . v. Goodin , 743

16 In Dixie Fuel Co. , an administrative law judge concluded that a medical report was not cr edible because th e physician had relied partly on medical articles that did not support the physician’s conc lusions. 820 F.3d at 845-46. The employer argued that the administrati ve law judge had improperly “play[ed] expert” by examining the medical articles. Id. at 845. The Sixth Circuit disagree d, explaining that the administrative law judge had “merely fulfilled his role as fact-finder by ev aluating the credibility of [the physician’s ] conclusions.” Id.25 F.3d 1331, 1345-46 (10th Cir. 2014); 17 see also Consol. Coal Co. v. Dir., Office of Workers Comp. Programs , 732 F.3d 723, 735 (7th Cir. 2013) (holding that the administrative law j udge did not err by discrediting the medical opinion of a doctor who had relied on general statistics because the doctor had not related these statis tics to the particular coal-mining employee). We theref ore reject Energy West’s argument.
D. Judge Johnson did not improp erly rely on the “preamble” to the applicable regulations. Energy West also argues that Judg e Johnson improper ly relied on the “preamble” to the appl icable regulations. 18 According to Energy West, Judge Johnson treated the preamble as the law ev en though the preamblehad not been subject to the Administrative Procedure Act’s notice-andcomment requirements.

17 In Goodin , the employer also presen ted testimony by medical experts, who had opined that a coal miner’s chronic obstructive pulmonary disease was statistically more likely to be caused by ci garettes or asthma than by inhalation of coal-mine dust. 743 F. 3d at 1339, 1345. The administrative law judge re jected 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 pulmo nary disease from coal mining. Id. at 1345-46. We upheld this ra tionale as adequately s upported by the record. Id. at 1346.

18 The preamble to th e 2001 amendments to the black lung regulations provides the medical prin ciples that underlie the Department of Labor’s current regulations. See Regulations Implementing the Federal Coal Mine Health and Safety Act of 1969, as am ended, 65 Fed. Re g. 79,920, 79,920- 80,045 (Dec. 20, 2000).26 We disagree based on our tr eatment of the issue in Blue Mountain Energy v. Director, Office of Workers’ Co mpensation Programs , 805 F.3d 1254 (10th Cir. 2015). Ther e we distinguished between two distinct uses of the preamble. In one, an administrative law judg e uses the preamble to “effect[] some sort of cha nge in the law” or to cr eate “a broadl y-applicable rule.” 805 F.3d at 1261. This use of the preamble is improper. Id. But an administrative law judge ca n consider the preamble as a tool to gauge an expert’s credibility. See id. Because the administra tive law judge in Blue
Mountain had used the preamble only as a tool to we igh the causation evidence for that case (rather than fo r a broader legal principle), we did not fault the Board for affirming the administra tive law judge’s decision. Id. at 1261-62. This dichotomy guides our consideration of Judge Johnson’s use of the preamble. Energy West points to two of Judg e Johnson’s statements: (1) that Doctor Fa rney’s understanding of how co al-mine dust and cigarette smoke affects the lungs wa s “contrary to the prem ise underlying the Black Lung regulations,” and (2 ) that Doctor Farney had failed to acknowledge the Department of Labor’s recognition of the additi ve 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 j udge’s language refers to analysis of the evid ence “in this case.” Blue Mountain , 805 F.3d at 126127 (emphasis omitted). After discussing the premises underlyi ng the preamble, Judge Johnson indicated that

 he understood that all issues “m ust be resolved on a claim-byclaim 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 near ly identical to the administrative la w 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 dis ease, an etiology clearly adopte d in the Preamble to the Regulations. . . . Dr . Parker specifically linked Claimant’s symptoms to the docu mented effects of coal mine exposure and cited to literature that has been approved by the Department in the Preamble

. Blue Mountain , 805 F.3d at 1261 (e mphasis modified) (e llipsis in original) (citation omitted). Here to o 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 th e medical opinions.” Petitioner’s Opening Br. at 34. Accord ing to Energy West, Judge Johnson’s use of the preamble was more expansiv e, using the preamble to conclude28 that “medical opinions which are based on the pr emise that coal dustrelated obstructive disease is comple tely distinct from smoking-related disease are errant” and that “coal du st and smoking . . . always have additive effects.” Petition er’s Opening Br. at 33 , 45 (emphasis omitted). We disagree. Judge Johns on simply pointe d out that Doct or Farney was making unsupported assumptions that conflicte d with the preamble. Had Doctor Farney provided reasons for hi s assumptions, J udge Johnson would have been bound to consider them. See Blue Mountain , 805 F.3d at 1261 (“[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 J ohnson was overly generous in his consideration of Dr. James’s opin ion. This contention reflects a misunderstanding of how Judge Johnson applied Dr. James’s opinion. Judge Johnson did descri be 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 John son erred in discussing the preamble without a request by the claima nt, this argument is waived by omission in Energy West’s briefs. See United States v. Burns , 775 F.3d 1221, 1223 n.2 (10th Cir. 2014).29 well-reasoned.” Petitioner’s Opening Br., Attachme nt C at 16. But Judge Johnson simply concluded that Dr. Ja mes’s opinion had no t helped Energy West to rebut the presumption. Id. This conclusion appears unassailable. Energy West might disagree with Dr. Ja mes, but his opinion certainly did not help Energy West to rebut the presumption.
F. If Judge Johnson had erroneo usly used the wrong legal standard, the error would have been harmless. Finally, Energy West ar gues that Judge Johns on applied an improper legal standard that unfair ly 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 , 743 F.3d 1331, 1348 (10th Cir. 2014) (concluding that “a ny alleged error was harmless because Mr. Goodin would ha ve prevailed ev en without the [error]”). Energy West’s argument is straig htforward. A federal regulation allows Energy West to rebut the 15-ye ar presumption by establishing that Mr. Blackburn did not have lega l pneumoconiosis or clinical pneumoconiosis. 20 C.F.R. § 718.305(d)(1)(i). Only legal pneumoconiosis is at issue here, for no one conte nds that Mr. Blac kburn had clinical pneumoconiosis. A different federal regulation defines legal pneumoconiosis as a chronic lung di sease or impairment “arising out of coal mine employment.” Id. § 718.201(a)(2). The phrase “arising out of30 coal mine employment” “includes” any chronic disease or impairment

“ significantly related to, or substantially aggravated by ” dust from coalmine employment. Id. § 718.201(b) (emphasis added). According to Energy West, § 718.201(b) sets forth the relevant standard and Judge Johnson deviated from this standard by requiring En ergy West to co mpletely “rule out” any causal link between Mr. Blac kburn’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 an d 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 connec tion between coal-mine dust and Mr. Blackburn’s lung disease. Instead, J udge Johnson reason ed that Energy West’s evidence was not credible. Energy West asserts that “[e]va luation under the correct legal standard may have changed the credibility determinations.” Petitioner’s Opening Br. at 28. We di sagree. Judge Johnson rej ected Doctor Farney’s opinion because it had been unsuppo rted by the refe renced medical literature, had contained an inconsis tency, and had failed to address important issues. And Judge Johnson rejected Doctor Tuteur’s opinion because it had relied on statistics ra ther than on Mr. Blackburn as an31 individual. The rebuttal standard did no t affect Judge John son’s analysis of either doctor’s opinion. Energy West argues that a Board case, Minich v. Keystone Coal Mining Corp. , demonstrates that any erro r 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 addr ess harmlessness because the administrative law judge’s conclusion there had result ed directly from the administrative law judge’s use of the wrong legal standard. Ther e one doctor had found that the effect of coal -mine dust was “insignifi cant,” 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 phy sicians could not exclud e the possibility that exposure to coal-mine dust had contri buted to the claima nt’s disability. Id. at 1-157 to -158. The Board agreed wi th the employer’s criticism of the rule-out standard and vacated the administrative law judge’s decision awarding benefits to the coal miner. Id. at 1-158.
In Minich , the Board never mentioned harmlessness or an issue involving the credibility or persua siveness of the doctors’ opinions. See id. Presumably, these considerations appeared unimportant because the administrative law judge ha d taken the doctors’ op inions at face value. Doing so, the admini strative law judge had reas oned that th e doctors’32 opinions would require an award of be nefits under the rule-out standard. See id. That is not the case here, for Judge Johnson did not take the medical opinions at face value. In stead, Judge Johnson deci ded that the opinions of Doctor Farney and Doctor Tuteur we re not credible. In reaching this decision, Judge John son 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.