                     FOR PUBLICATION

    UNITED STATES COURT OF APPEALS
         FOR THE NINTH CIRCUIT


 PEABODY COAL COMPANY,                             No. 12-70535
                     Petitioner,
                                                     BRB No.
                     v.                              10-0463

 DIRECTOR, OFFICE OF WORKERS’
 COMPENSATION PROGRAMS; U.S.                         OPINION
 DEPARTMENT OF LABOR; ROBERT
 DALE OPP, Deceased,

                             Respondents.


          On Petition for Review of an Order of the
                   Benefits Review Board

                    Submitted July 11, 2013*
                       Portland, Oregon

                       Filed April 1, 2014

         Before: Harry Pregerson, Mary H. Murguia,
            and Morgan Christen, Circuit Judges.

                  Opinion by Judge Pregerson


  *
    The panel unanimously concludes this case is suitable for decision
without oral argument. See Fed. R. App. P. 34(a)(2).
2                   PEABODY COAL V. OWCP

                           SUMMARY**


                    Black Lung Benefits Act

   The panel denied a petition for review of a decision of the
Benefits Review Board ordering Peabody Coal Company to
pay a coal miner’s surviving spouse benefits under the Black
Lung Benefits Act of 1972.

    The panel held that the administrative law judge did not
violate the Administrative Procedure Act by considering the
regulatory preamble to the Black Lung Benefits Act in his
decision awarding benefits. The panel held that a preamble
may be used to give an ALJ understanding of a scientific or
medical issue, and concluded that the ALJ properly
considered the regulatory preamble to evaluate conflicting
expert medical opinions. The panel also held that the ALJ’s
award of benefits was supported by substantial evidence.


                             COUNSEL

Mark E. Solomons and Laura Metcoff Klaus, Greenberg
Traurig, LLP, Washington, D.C., for Petitioner.

Jeffrey S. Goldberg, United States Department of Labor,
Washington, D.C., for Respondent.

Martin J. Linnet and Jonathan Wilderman, Wilderman and
Linnet, P.C., Golden, Colorado, for Respondent.

  **
     This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
                     PEABODY COAL V. OWCP                              3

                              OPINION

PREGERSON, Circuit Judge:

    In 2000, Robert Opp (“Opp”) filed a disability benefits
claim against Peabody Coal Company (“Peabody”) under the
Black Lung Benefits Act of 1972. 30 U.S.C. § 901(a). Opp,
a coal miner for nearly forty years, smoked for over fifty
years. In the mid-1990s, Opp began suffering from chronic
obstructive pulmonary disease (“COPD”). Opp alleged that
his COPD arose out of his employment as a coal miner.
When a claimant proves total disability due to either clinical
pneumoconiosis or legal pneumoconiosis, the claimant is
eligible for benefits under the Black Lung Benefits Act. See
20 C.F.R. § 718.201(a). Opp alleged that his condition
constituted legal pneumoconiosis and that he was entitled to
benefits under the Act.1

    Following a number of administrative hearings and
reviews by the Benefits Review Board, an administrative law
judge (“ALJ”) ordered Peabody to pay Opp’s surviving
spouse all the benefits to which Opp was entitled to receive
between January 1, 2000, and August 31, 2002. The Benefits
Review Board affirmed the ALJ’s decision and Peabody Coal
petitions for review of that decision. We have jurisdiction to
review Peabody’s petition pursuant to 33 U.S.C. § 921(c),
and we deny the petition.




 1
     Following Opp’s death in 2002, his widow has pursued his claim.
4                    PEABODY COAL V. OWCP

                         I. BACKGROUND

A. Factual History

        1. The Statute and Regulations

   The Black Lung Benefits Act awards benefits to coal
miners suffering from pneumoconiosis, defined as “a chronic
dust disease of the lung and its sequelae, including respiratory
and pulmonary impairments, arising out of coal mine
employment.” 30 U.S.C. § 902(b). A disease arises out of
coal mine employment if it is “significantly related to, or
substantially aggravated by, dust exposure in coal mine
employment.” 20 C.F.R. § 718.201(b).

    Before 2001, the Black Lung Benefits Act regulations
provided that coal miners suffering from clinical
pneumoconiosis were eligible for benefits under the Act.
20 C.F.R. § 718.201(a) (2000). Clinical pneumoconiosis
refers to a cluster of typically chronic restrictive pulmonary
diseases recognized by the medical community as fibrotic
reactions to “permanent deposition of substantial amounts of
particulate matter in the lungs.” 20 C.F.R. § 718.201(a)(1).
In 2001, the regulations were amended to clarify that coal
miners suffering from legal pneumoconiosis may also receive
benefits under the Act. Legal pneumoconiosis refers to “any
chronic lung disease or impairment,” including “chronic
restrictive or obstructive pulmonary disease arising out of
coal mine employment.”2 20 C.F.R. § 718.201(a)(2)


    2
    Restrictive lung disease, or interstitial lung disease, makes it difficult
to fill the lungs with air, and for the body to get enough oxygen. National
Institutes of Health, Interstitial Lung Diseases, MedlinePlus,
http://www.nlm.nih.gov/medlineplus/interstitiallungdiseases.html (last
                    PEABODY COAL V. OWCP                              5

(emphasis added). Before Opp’s death, he suffered from
COPD, which he alleged was a form of legal
pneumoconiosis.

    2. The Regulatory Preamble

      The preamble to the 2001 amendments that clarify the
regulatory definition of pneumoconiosis explains that the
amendments were intended to “conform [the regulatory
definition] to the statute,” which defines pneumoconiosis
broadly. 65 Fed. Reg. at 79937. “The Department [of Labor]
. . . received both favorable and unfavorable comments on its
proposed revision to the definition of pneumoconiosis.” Id.
During the notice and comment period, several of the
unfavorable comments referred to a review of the available
medical literature on obstructive lung disease and pulmonary
dysfunction in coal miners, written by Dr. Gregory Fino, a
Board-certified physician in pulmonary diseases, and Dr.
Barbara Bahl, a doctor in nursing and biostatistics. Id. at
79938. Dr. Fino’s and Dr. Bahl’s “review of the literature . . .
led them to conclude that virtually all of the articles they
reviewed [were] flawed, and that there [was] no evidence of
a clinically significant reduction in lung function resulting
from coal mine dust exposure.” Id.




updated July 22, 2013). Obstructive lung disease includes three disease
processes that make it difficult to empty the lungs of air: (1) chronic
bronchitis, (2) emphysema, and (3) asthma. Regulations Implementing the
Federal Coal Mine Health and Safety Act of 1969, as Amended, 65 Fed.
Reg. 79920, 79939 (Dec. 20, 2000); National Institutes of Health, What
is COPD?, National Heart, Lung, and Blood Institute,
http://www.nhlbi.nih.gov/health/health-topics/topics/copd/ (last updated
July 31, 2013).
6                PEABODY COAL V. OWCP

    In the preamble, the Department of Labor observed that
Dr. Fino’s and Dr. Bahl’s “opinions [were] not in accord with
the prevailing view of the medical community or the
substantial weight of the medical and scientific literature.”
Id. at 79939. The preamble addressed several studies in the
medical record that “contain overwhelming scientific and
medical evidence demonstrating that coal mine dust exposure
can cause obstructive lung disease.” Id. at 79944; see id. at
79941–44.

     The preamble first evaluated the medical and scientific
literature on chronic bronchitis. The Oxman study, for
instance, “found a statistically significant association between
cumulative dust exposure and decline in lung function.” Id.
at 79939 (citing A.D. Oxman et al., Occupational Dust
Exposure and Chronic Obstructive Pulmonary Disease: A
Systematic Overview of the Evidence, 148 Am. Rev.
Respiratory Disease 38 (1993)). The Oxman study likely
“underestimates the association between inhalation of coal
mine dust and loss of lung function” because unhealthy
workers tend to exit the workforce. Id. (emphasis omitted).
Likewise, the Marine study found that “[e]ven in the absence
of smoking, coal mine dust exposure is clearly associated
with clinically significant airways obstruction and chronic
bronchitis.” Id. at 77940 (citing W.M. Marine et al.,
Clinically Important Respiratory Effects of Dust Exposure
and Smoking in British Coal Miners, 137 Am. Rev.
Respiratory Disease 106 (1988)). The Marine study found
that “[t]he risk [of airways obstruction resulting from coal
mine dust exposure] is additive with cigarette smoking.” Id.
Studies similar to the Marine study, such as the Attfield and
Hodous study, “demonstrated a clear relationship between
dust exposure and a decline in pulmonary function [in coal
miners] of about 5 to 9 milliliters a year.” Id. (citing M.D.
                 PEABODY COAL V. OWCP                       7

Attfield & T.K. Hodous, Pulmonary Function of U.S. Coal
Miners Related to Dust Exposure Estimates, 145 Am. Rev.
Respiratory Disease 605 (1992)). According to Attfield and
Hodous, the “average decrement for smokers was only 5ml”
per pack-year of smoking. Id. at 79941 (quoting 145 Am.
Rev. Respiratory Disease at 608).

     The preamble next evaluated the medical and scientific
literature on emphysema. The Cockcroft study found that
centrilobular emphysema “was significantly more common
among . . . coal workers” and “related to the amount of dust
in the lungs.” Id. (citing A. Cockcroft et al., Post-mortem
Study of Emphysema in Coalworkers and Non-Coalworkers,
2 Lancet 600 (1982)). The Leigh study found “strong
evidence that emphysema in coalworkers is causally related
to lung coal content.” Id. at 79942 (quoting J. Leigh et al.,
Quantified Pathology of Emphysema, Pneumoconiosis and
Chronic Bronchitis in Coal Workers, 40 Brit. J. Indus. Med.
258 (1983)). The Ruckley study also found evidence of a
causal connection between coal dust exposure and
emphysema. Id. (citing V.A. Ruckley et al., Emphysema and
Dust Exposure in a Group of Coal Workers, 129 Am. Rev.
Respiratory Disease 528 (1984)). Dr. Fino and Dr. Bahl cited
several sources supporting the contention that there is no
causal connection between coal dust exposure and
emphysema. The preamble noted that Dr. Fino and Dr. Bahl
quoted a passage from a textbook on occupational lung
disease to support their assertion that focal emphysema
cannot be equated with airways obstruction. Id. (citing
Occupational Lung Diseases (W. Keith C. Morgan &
Anthony Seaton eds., (3d ed. 1995))). But the preamble also
noted another passage from the same textbook that stated
“[t]he increased risk of centriacinar emphysema . . . supports
the hypothesis that coal dust exposure sufficient to cause
8                PEABODY COAL V. OWCP

alveolar inflammation and fibrosis also initiates centriacinar
emphysema.” Id. (quoting Occupational Lung Diseases at
400–401).

    3. The Relevant Testimony

    At his administrative hearing in 2000, Opp testified about
his smoking history and coal mine employment. Opp worked
as a coal miner for thirty-nine years and smoked between
one-half and one and a half packs of cigarettes a day for
around fifty-two years. Opp testified that “a lot of times” he
quit smoking for “six or seven months at a time.” He said
that he “[m]ight have only smoked four months some of the[]
years,” while other years he may have “smoked [for] eight”
months.

    As a coal miner, Opp worked on the surface of the mine.
He operated an end loader during the last fifteen years of his
coal mine employment. Opp described his work environment
as dusty to “real bad.” He said the dust saturated all the way
through his clothing to his skin, and that within a half hour of
starting work, his clean clothes would be dirty.

    In 1989, Opp was forced to retire after he broke his back
during a fall from the radiator of a haul truck. Opp
underwent surgery for this injury. He testified that his
breathing problems were “just starting” when he injured his
back.

    Two medical experts testified that Opp’s respiratory
impairment was attributable to his employment as a coal
miner. In 2000, the Department of Labor provided for an
examination of Opp by physician David James. Opp testified
that he told Dr. James that he “had been short of breath” since
                 PEABODY COAL V. OWCP                        9

1994 or 1995. Dr. James diagnosed Opp with: (1) coal
workers’ legal pneumoconiosis, attributable to coal dust
exposure; (2) COPD, attributable to coal dust exposure and
smoking; and, (3) exercise-induced desaturation of oxygen,
attributable to pneumoconiosis and COPD. Dr. James
concluded that “chronic exposure to coal mine dust [was] a
contributing factor to [Opp’s] total disability and severe
respiratory impairment.”

     In 2001, Opp’s treating physician, William Anderson,
prepared a report on Opp’s respiratory condition. Dr.
Anderson expressed the opinion that Opp was suffering from
COPD and concluded that coal dust exposure “most probably
[was] a contributing factor . . . due to [Opp’s] severe disease
at [the] relatively young age [of 68].”

     Peabody’s four medical experts, who assessed Opp’s
respiratory impairment between 2000 and 2001, testified that
Opp’s respiratory impairment was not attributable to his coal
mine employment. In 2000, Dr. Lawrence Repsher examined
Opp and diagnosed him with COPD unrelated to coal dust
exposure. Dr. Repsher concluded that Opp did not have coal
workers’ pneumoconiosis because he believed that coal dust
has primarily restrictive, rather than obstructive effects. At
his deposition, Dr. Repsher testified that “the coal mine dust
literature”does not provide evidence that coal dust exposure
can cause “clinically significant [COPD]” in a miner who
never smoked.

     In 2001, Dr. Peter Tuteur prepared a report based on
Opp’s medical record. Dr. Tuteur described Opp’s symptoms
as “quintessentially characteristic of . . . [COPD].” Dr.
Tuteur testified that “[t]here’s no credible evidence in the
literature to indicate that coal mine dust inhalation acts
10               PEABODY COAL V. OWCP

additively or synergistically with the chronic inhalation of
tobacco smoke to promote [COPD].”

    Also in 2001, Dr. Joseph Renn prepared a report based on
Opp’s medical record. Dr. Renn diagnosed Opp with
“chronic bronchitis with an asthmatic component and
pulmonary emphysema,” all stemming from tobacco smoking
rather than exposure to coal mine dust.

    Finally, Dr. Fino, in 2001, prepared a report based on
Opp’s medical record. Dr. Fino diagnosed Opp with bullous
emphysema, “a classic pattern that one would expect as a
result of cigarette smoking.” At his deposition, however, Dr.
Fino admitted the possibility of a coal-dust-induced disease
“in a susceptible individual.”

B. Procedural History

     During a lengthy procedural process, the ALJ twice
awarded and twice denied benefits. The Benefits Review
Board remanded the case to the ALJ three times. In its 2009
remand to the ALJ, the Benefits Review Board explicitly
permitted the ALJ to review the medical literature in the
record to determine whether Dr. James, who believed that
Opp’s COPD was caused in part by coal dust, “accurately
characterized the literature.” The Benefits Review Board also
permitted the ALJ to consider “whether the criticisms that
[Peabody’s] experts have raised concerning the studies [that
Dr. James relied on] have merit.” The ALJ properly
construed this to mean that he should assess whether
Peabody’s experts accurately characterized and critiqued the
literature.
                 PEABODY COAL V. OWCP                      11

    In evaluating the merit and accuracy of the medical expert
testimony, the ALJ relied, in part, on the regulatory preamble
to 20 C.F.R. § 718.201(a), the regulation defining coal
workers’ pneumoconiosis. See 65 Fed. Reg. at 79937–45.
The ALJ concluded that Dr. James’s and Dr. Anderson’s
opinions that coal dust exposure contributed to Opp’s COPD
were well reasoned and documented. The ALJ also
concluded that Dr. James accurately characterized the
medical literature. In contrast, the ALJ found that Peabody’s
doctors’ opinions should be discounted and accorded
diminished evidentiary weight because their negative
characterization of the medical literature was not in accord
with prevailing medical views, as set forth in the regulatory
preamble. The ALJ also found “substantial equivalency”
between coal dust conditions in Opp’s work on the surface of
the mine and “underground coal mine work.”

    The ALJ concluded that Opp’s legal pneumoconiosis
arose out of coal mine employment, and that Opp’s coal mine
employment was “a substantial contributing cause of [Opp’s]
totally disabling . . . pulmonary impairment.” The ALJ
ordered Peabody to pay Opp’s surviving spouse all the
benefits to which Opp was entitled between January 1, 2000,
and August 31, 2002. The Benefits Review Board affirmed
the ALJ’s decision in 2011. Peabody appeals.

                      II. ANALYSIS

A. The ALJ Did Not Violate the Administrative
   Procedure Act by Considering the Preamble.

    Peabody challenges the ALJ’s reliance on the regulatory
preamble in his decision awarding benefits to Opp. Peabody
argues that the ALJ impermissibly gave the regulatory
12               PEABODY COAL V. OWCP

preamble the force of law in violation of the Administrative
Procedure Act. This challenge therefore presents a question
of law that we review de novo. Valladolid v. Pac. Operations
Offshore, LLP, 604 F.3d 1126, 1130 (9th Cir. 2010).

    The Black Lung Benefits Act requires that regulations be
issued in conformity with 5 U.S.C. § 553 of the
Administrative Procedure Act. 30 U.S.C. § 936(a). Pursuant
to § 553, regulations may be promulgated following a period
of notice and comment. A regulatory preamble, such as the
one at issue in this case, is not subject to notice and comment.
As a result, the preamble is not legally binding. See § 936(a).

    In 2002, mine operators, insurance companies, and the
National Mining Association (collectively, the “NMA”)
challenged the legality of the preamble at issue in this case.
Nat’l Mining Ass’n v. Dep’t of Labor, 292 F.3d 849, 855
(D.C. Cir. 2002). The NMA was concerned that coal mine
workers with lung impairments who also smoked would be
presumed eligible for benefits and the preamble would
impermissibly be given the force of law. The United Mine
Workers of America and other black lung advocates
intervened on behalf of the Secretary of Labor, arguing in
favor of the regulations and the preamble. Id. The D.C.
Circuit upheld the regulations in all respects, confirming that
the preamble does not diminish the requirement that miners
individually demonstrate their lung impairments arose out of
coal mining employment: “[T]he preamble itself states that
the revised definition [of pneumoconiosis] does not alter the
requirement that individual miners must demonstrate that
their obstructive lung disease arose out of their work in the
mines.” Id. at 863 (citing 65 Fed. Reg. at 79938).
                   PEABODY COAL V. OWCP                            13

    Here, Peabody argues that (1) Opp has not demonstrated
that his COPD arose from coal mine employment, and (2) the
ALJ impermissibly relied on the preamble to award benefits.
We find, however, that the ALJ simply—and not
improperly—considered the regulatory preamble to evaluate
conflicting expert medical opinions. The ALJ then evaluated
the record to determine that Opp’s condition did, in fact, arise
from coal mine employment.

    A preamble may be used to give an ALJ understanding of
a scientific or medical issue. The ALJ’s reliance on the
regulatory preamble has been explicitly endorsed by various
courts of appeal and the Benefits Review Board. See A & E
Coal Co. v. Adams, 694 F.3d 798, 802 (6th Cir. 2012)
(explaining that the preamble “merely explains why the
regulations were amended” and did “not expand their
reach”);3 Harman Mining Co. v. Dir., Office of Workers’
Comp. Programs, 678 F.3d 305, 314–15 (4th Cir. 2012)
(concluding that “the ALJ was entitled to” look to the
preamble to assess a medical expert’s credibility); Helen
Mining Co. v. Dir., Office of Workers’ Comp. Programs,
650 F.3d 248, 257 (3d Cir. 2011) (stating “[t]he ALJ’s
reference to the preamble . . . unquestionably supports the
reasonableness of his decision to assign less weight” to a
medical expert’s opinion); Consolidation Coal Co. v. Dir.,
Office of Workers’ Comp. Programs, 521 F.3d 723, 726 (7th
Cir. 2008) (describing as “sensible” an ALJ’s decision to
discredit a medical expert’s opinion that was inconsistent
with the preamble); Ethel Groves v. Island Creek Coal Co.,
BRB No. 10-0592, 2011 WL 2781446, at *3 (DOL Ben. Rev.
Bd. June 23, 2011) (ruling that “an administrative law judge

   3
     In A & E Coal Co., the petitioner presented—and the Sixth Circuit
rejected—the same argument Peabody presents here.
14               PEABODY COAL V. OWCP

has the discretion to examine whether a physician’s reasoning
is consistent with the conclusions contained in medical
literature and scientific studies relied upon by [the
Department of Labor] in drafting the definition of legal
pneumoconiosis”).

    Peabody relies on Wyeth v. Levine, 555 U.S. 555 (2009)
and Home Concrete & Supply, LLC v. United States, 634 F.3d
249 (4th Cir. 2011) to argue that we should be wary of
preambles that rewrite or significantly supplement regulations
and statutes. In the case before us, however, the preamble
does no such thing. It is consistent with the Black Lung
Benefits Act and its regulations. Thus, Wyeth and Home
Concrete & Supply are inapposite.

    In Wyeth, the drug company Wyeth failed to warn about
the consequences of administering a drug through the IV push
method. 555 U.S. 555, 559–60 (2009). Wyeth argued that
Levine’s state law claims were preempted as an obstacle to
federal regulation because: (1) the drug’s label complied with
the Federal Drug Administration (“FDA”) regulations, and
(2) the 2006 preamble to an FDA regulation declared that
state law failure-to-warn claims “threaten the FDA’s
statutorily prescribed role as the expert Federal agency
responsible for evaluating and regulating drugs.” Id. at
575–76 (internal quotation marks and citation omitted). The
contested preamble in Wyeth contained an agency’s legal
interpretation, and not, as in the case before us, a fact-based
explanation of the agency’s interpretation in light of
empirical research. In Wyeth, “[w]hen the FDA issued its
notice of proposed rulemaking in December 2000, it
explained that the rule would not contain policies that have
federalism implications or that preempt State law.” Id. at 577
(internal quotation marks and citation omitted). Thus, the
                 PEABODY COAL V. OWCP                       15

preamble at issue in Wyeth provided a legal interpretation that
“reverse[d] the FDA’s own longstanding position without
providing a reasoned explanation,” and this is why the Court
ruled that the preamble “[did] not merit deference.” Id.

    Peabody’s reliance on Home Concrete & Supply is
similarly misplaced. Home Concrete & Supply discusses the
period of time in which the Internal Revenue Service (“IRS”)
may make certain kinds of tax assessments under 26 U.S.C.
§ 6501. 634 F.3d 249 (4th Cir. 2011). In Home Concrete &
Supply, the IRS argued that, pursuant to the preamble of
Treasury Decision 9511, the “six-year period for assessing
tax” remained open for “all taxable years . . . that are the
subject of any case pending before any court of competent
jurisdiction . . . in which a decision had not become final.”
Id. at 256 (internal quotation marks and citation omitted). In
§ 6501(a), however, Congress provided that the window for
tax assessments closed after three years, barring special
circumstances. Thus, the Fourth Circuit denied force to the
preamble at issue in Home Concrete & Supply because it
contradicted plain statutory language. 634 F.3d at 256–57.

      In short, unlike the preambles in Wyeth and Home
Concrete & Supply, the preamble in the case before us is
“entirely consistent with the [Black Lung Benefits] Act and
its regulations.” Harman Mining Co., 678 F.3d at 315 n.4.
Like the preamble we addressed in El Comite Para el
Bienestar de Earlimart v. Warmerdam, the preamble in this
case “aid[s] in achieving a general understanding of the
statute,” 539 F.3d 1062, 1070 (9th Cir. 2008) (internal
quotation marks and citation omitted), because it “simply
explains the scientific and medical basis for the regulations”
that extended the definition of pneumoconiosis, Harman
Mining Co., 678 F.3d at 315 n.4. The preamble discusses the
16               PEABODY COAL V. OWCP

medical and scientific literature included in the record at the
time the Department of Labor amended the regulation
defining pneumoconiosis. The evidence supports the
conclusion that coal dust exposure contributes to chronic
obstructive disease.

   Thus, we join our sister circuits in holding that an ALJ
may consider the regulatory preamble.

B. The ALJ’s Award of Benefits to Opp is Supported by
   Substantial Evidence.

    Absent error of law, the ALJ’s findings and conclusions
must be affirmed if supported by substantial evidence.
Palmer Coking Coal Co. v. Dir., Office of Workers’ Comp.
Programs, 720 F.2d 1054, 1056 (9th Cir. 1983). Substantial
evidence is such evidence that a reasonable mind might
accept as adequate to support a conclusion. Conahan v.
Sebelius, 659 F.3d 1246, 1249 (9th Cir. 2011). “The
substantial evidence test for upholding factual findings is
‘extremely deferential to the factfinder.’”        Rhine v.
Stevedoring Servs. of Am., 596 F.3d 1161, 1165 (9th Cir.
2010) (quoting Metro. Stevedore Co. v. Rambo, 521 U.S. 121,
149 (1997)). In weighing medical evidence, “the ALJ is free
to credit a witness’s testimony in the face of one party’s
argument that the witness is not credible.” Haw. Stevedores,
Inc. v. Ogawa, 608 F.3d 642, 650 (9th Cir. 2010).

    After assessing the expert medical testimony, the ALJ
found that Opp’s COPD arose out of his coal mine
employment. The ALJ rationally credited Dr. James’s
opinion as well supported and reasoned. Dr. James relied on
a number of factors to conclude that Opp’s COPD was caused
by smoking and coal dust exposure, including: (1) Opp’s
                 PEABODY COAL V. OWCP                        17

medical, smoking, and employment histories; (2) medical
literature showing that coal mine dust can cause airflow
obstruction in miners whose x-rays do not show evidence of
fibrotic disease; (3) the limited reversibility of Opp’s
condition after use of a bronchodilator; and (4) the unusual
severity of Opp’s impairment.

    The ALJ rationally discounted the testimony of Peabody’s
medical experts, who based their opinions on the premise that
coal dust exposure never, or very rarely, causes COPD. The
ALJ permissibly looked to the preamble to determine that
Peabody’s medical experts proffered only one of several
interpretations of the evidence. The ALJ concluded that, in
light of the preamble’s interpretation of the conflicting
medical evidence included in the medical record, Peabody’s
medical experts’ opinions were appropriately afforded less
weight. To reverse the ALJ’s findings on substantial
evidence review in a black lung disability case “we would
have to find that [Peabody’s medical experts’] interpretation
[of the evidence] was the only permissible one.” Midland
Coal Co. v. Dir., Office of Workers’ Comp. Programs,
358 F.3d 486, 492 (7th Cir. 2004). Because “there is
considerable basic scientific data linking coal mine dust to the
development of obstructive airways disease,” the ALJ
properly discounted the contrary view advanced by
Peabody’s experts. 65 Fed. Reg. at 79943.

    Accordingly, the ALJ’s decision to credit Dr. James’s and
Dr. Anderson’s testimony and to afford diminished weight to
Peabody’s medical experts’ testimony is supported by
substantial evidence.
18              PEABODY COAL V. OWCP

                     CONCLUSION

    Because the agency’s award of benefits to Opp is
supported by substantial evidence, we deny Peabody’s
petition for review.

     Petition for review DENIED.
