Roy A. Gray v. Donaldson Mine Company and Valley Camp Coal Company (Board decision, September 30, 2020)

BRB final decision. This unpublished decision is not precedent. A Board decision ordinarily becomes final 60 days after issuance unless a timely petition for judicial review or Board reconsideration is filed under 20 C.F.R. § 802.406. A party may request Board reconsideration within 30 days under 20 C.F.R. § 802.407.

Plain-English summary

Roy Gray received black lung benefits after a judge found more than nineteen years of underground mine work and total respiratory disability. The employer and carrier challenged the disability finding, the fifteen-year presumption, and the judge’s explanation of rebuttal. The Board upheld the judge’s findings and affirmed the award.

Decision snapshot

• Authority: The presumption and rebuttal under 30 U.S.C. § 921(c)(4) and 20 C.F.R. § 718.305.
• Outcome: Benefits award affirmed.
• Key point: The employer did not overturn the disability finding or rebut the presumption.

Full text (DOL BRB public release)

U.S. Department of Labor Benefits Review Board 200 Constitution Ave. NW
Washington, DC 20210-0001

BRB No. 19-0469 BLA

ROY A. GRAY
)
)
Claimant-Respondent
)
)
v. )
)
DONALDSON MINE COMPANY
) DATE ISSUED: 09/30/2020
)
and
)
)
VALLEY CAMP COAL COMPANY
)
)
Employer/Carrier-
)
Petitioners
)
)
DIRECTOR, OFFICE OF WORKERS’
)
COMPENSATION PROGRAMS, UNITED
)
STATES DEPARTMENT OF LABOR
)
)
Party-in-Interest
) DECISION and ORDER

Appeal of the Decision and Order Awarding Benefits of Lauren C. Boucher, Administrative Law Judge, United States Department of Labor.

Joseph E. Wolfe and Brad A. Austin (Wolfe Williams & Reynolds), Norton, Virginia, for Claimant.

Ann B. Rembrandt (Jackson Kelly PLLC), Charleston, West Virginia, for Employer/Carrier.

Before: BOGGS, Chief Administrative Law Judge, BUZZARD and GRESH, Administrative Appeals Judges.
PER CURIAM:

Employer and its Carrier (Employer) appeal Administrative Law Judge Lauren C.
Boucher’s Decision and Order Awarding Benefits (2018-BLA-05809) rendered on a claim filed pursuant to the Black Lung Benefits Act, as amended, 30 U.S.C. §§901-944 (2018) (Act). This case involves a miner’s claim filed on March 16, 2017.1

The administrative law judge credited Claimant with 19.31 years of underground coal mine employment and found he has a totally disabling respiratory impairment. She therefore found Claimant invoked the presumption of total disability due to pneumoconiosis at Section 411(c)(4) of the Act, 30 U.S.C. §921(c)(4) (2018).2 She further found Employer did not rebut the presumption and awarded benefits.

Employer argues the administrative law judge erred in finding Claimant established total disability and invoked the Section 411(c)(4) presumption. Employer further alleges she erred in determining it did not rebut the presumption and did not comply with the Administrative Procedure Act (APA)3 in rendering her findings. Claimant responds in support of the award of benefits. The Director, Office of Workers’ Compensation Programs, did not file a response brief.4

The Benefits Review Board’s scope of review is defined by statute. We must affirm the administrative law judge’s Decision and Order if it is rational, supported by substantial

1
Claimant previously filed a claim, but withdrew it. A withdrawn claim is considered “not to have been filed.” 20 C.F.R. §725.306(b); Director’s Exhibit 1.
2
Under Section 411(c)(4) of the Act, Claimant is presumed totally disabled due to pneumoconiosis if he establishes at least fifteen years of underground or substantially similar surface coal mine employment, and a totally disabling respiratory or pulmonary impairment. 30 U.S.C. §921(c)(4) (2018); 20 C.F.R. §718.305.
3
The Administrative Procedure Act provides that every adjudicatory decision must be accompanied by a statement of “findings and conclusions and the reasons or basis therefor, on all the material issues of fact, law, or discretion presented . . . .” 5 U.S.C.
§557(c)(3)(A), as incorporated into the Act by 30 U.S.C. §932(a).

We affirm, as unchallenged on appeal, the administrative law judge’s finding that 4

Claimant has 19.31 years of qualifying coal mine employment. See Skrack v. Island Creek Coal Co., 6 BLR 1-710, 1-711 (1983); Decision and Order at 8. evidence and in accordance with applicable law.5 33 U.S.C. §921(b)(3), as incorporated by 30 U.S.C. §932(a); O’Keeffe v. Smith, Hinchman & Grylls Associates, Inc., 380 U.S. 359 (1965).

Invocation of the Section 411(c)(4) Presumption - Total Disability

A miner is totally disabled if his pulmonary or respiratory impairment, standing alone, prevents him from performing his usual coal mine work. 20 C.F.R. §718.204(b)(1). A claimant may establish total disability based on qualifying6 pulmonary function studies or arterial blood gas studies, evidence of pneumoconiosis and cor pulmonale with right- sided congestive heart failure, or medical opinions. 20 C.F.R. §718.204(b)(2)(i)-(iv). The administrative law judge must weigh all relevant supporting evidence against all relevant contrary evidence. See Rafferty v. Jones & Laughlin Steel Corp., 9 BLR 1-231, 1-232 (1987); Shedlock v. Bethlehem Mines Corp., 9 BLR 1-195, 1-198 (1986), aff’d on recon., 9 BLR 1-236 (1987) (en banc). The administrative law judge found total disability established based on the blood gas studies and medical opinions.7

The administrative law judge considered the results of five blood gas studies dated June 13, 2017, August 14, 2018, December 2, 2018, and January 9, 2019. 20 C.F.R.
§718.204(b)(2)(ii); Decision and Order at 11-13; Director’s Exhibit 13; Claimant’s Exhibits 2, 3; Employer’s Exhibit 1. Dr. Nader initially administered a resting study on June 13, 2017, which produced qualifying values. Director’s Exhibit 13. Dr. Nader then conducted a second resting study to “confirm hypoxemia.” Id. This study also produced

5
This case arises within the jurisdiction of the United States Court of Appeals for the Fourth Circuit, as Claimant’s coal mine employment occurred in West Virginia. See Shupe v. Director, OWCP, 12 BLR 1-200, 1-202 (1989) (en banc); Hearing Transcript at 16.
6
A “qualifying” pulmonary function study or blood gas study yields values that are equal to or less than the applicable table values listed in Appendices B and C of 20 C.F.R. Part 718. A “non-qualifying” study exceeds those values. 20 C.F.R. §718.204(b)(2)(i), (ii).
7
The administrative law judge found the pulmonary function studies do not establish total disability, as none of the studies produced qualifying values. 20 C.F.R.
§718.204(b)(2)(i); Decision and Order at 9-10; Director’s Exhibit 13; Claimant’s Exhibits 2, 3; Employer’s Exhibit 1. Because the administrative law judge found no evidence of cor pulmonale with right-sided congestive heart failure, she also found total disability was not established under 20 C.F.R. §718.204(b)(2)(iii). Decision and Order at 9 n.9.

3 qualifying values.8 Id. The August 14, 2018 study that Dr. Green administered and the December 2, 2018 study Dr. Mabe administered produced non-qualifying values at rest and qualifying values with exercise. Claimant’s Exhibits 2, 3. Dr. Zaldivar’s January 9, 2019 study produced non-qualifying values both at rest and with exercise. Employer’s Exhibit 1. Finding the first June 13, 2017 study to be invalid based on concerns that Drs. Ajjarapu and Zaldivar raised, and according greater weight to the exercise studies, the administrative law judge found a preponderance of the blood gas studies established total disability. 20 C.F.R. §718.204(b)(2)(ii); Decision and Order at 11-13.

Employer argues the administrative law judge erred in finding the blood gas studies conducted in 2017 and 2018 outweighed the 2019 blood gas study as she did not properly determine the validity of the second resting study done on June 13, 2017. Employer further contends she did not properly consider the chronology of the studies and merely “counted heads” to resolve the conflict in the evidence. Employer’s Brief at 9-12. These allegations of error do not have merit.

Regarding the validity of the June 13, 2017 tests, the administrative law judge permissibly discredited Dr. Zaldivar’s “general disapproval” of the practices at Norton Community Hospital, the facility where the tests were administered, because he relied on “past interactions with this facility” rather than “objections that are specific to” the 2017 blood gas studies. Decision and Order at 11; see Compton v. Island Creek Coal Co., 211 F.3d 203, 211 (4th Cir. 2000); Underwood v. Elkay Mining, Inc., 105 F.3d 946, 949 (4th Cir. 1997).

Similarly, the administrative law judge considered Dr. Rosenberg’s opinion that the discrepancy between the two June 13, 2017 studies “may have been caused by Claimant lying in a supine position prior to the first study” but rationally dismissed this assertion as “simply speculation” because he did not provide any substantive support. Decision and Order at 12, citing Employer’s Exhibit 8 at 17; see Sterling Smokeless Coal Co. v. Akers, 131 F.3d 438, 441 (4th Cir. 1997). Noting Dr. Rosenberg did not suggest any problem with the second blood gas study, the administrative law judge permissibly concluded Employer failed in its burden to persuade her that the second study is invalid, although she was persuaded that the first study was unreliable. Decision and Order at 12, citing Vivian v. Director, OWCP, 7 BLR 1-360 (1984) (the party challenging the validity of a study has

8
Dr. Nader conducted the June 13, 2017 blood gas studies as part of the Department of Labor sponsored pulmonary examination. The first study produced a pCO2 of 33 with a pO2 of 59. It was drawn at 12:17 and analyzed at 12:20. The second study produced a pCO2 of 30 with a pO2 of 70. It was conducted at 12:28 and analyzed at 12:30. Dr. Gaziano validated the first blood gas study, but provided no opinion on the second study. Director’s Exhibit 13.
4 the burden to establish the results are suspect or unreliable). We therefore affirm the administrative law judge’s determination that the second 2017 resting blood gas study is qualifying, valid, and reliable to assess total disability. See Jeffries v. Director, OWCP, 6 BLR 1-1013, 1-1014 (1984).

We also reject Employer’s argument that because the blood gas studies do not indicate a permanent disability “when viewed on a continuum,” the administrative law judge erred in declining to give more weight to the January 9, 2019 non-qualifying blood gas study. Employer’s Brief at 12-13. The administrative law judge considered recency as a factor but accurately observed the January 9, 2019 blood gas study was “conducted only one month after Dr. Mabe’s [December 2, 2018] study and within six months of Dr. Green’s [August 14, 2018] study,” both of which produced qualifying exercise values. Decision and Order at 13. Thus, she permissibly concluded the January 9, 2019 study was not entitled to greater weight based on its date. Adkins v. Director, OWCP, 958 F.2d 49, 51-52 (4th Cir. 1992); Schetroma v. Director, OWCP, 18 BLR 1-19, 1-22 (1993); Wilt v. Wolverine Mining Co., 14 BLR 1-70 (1990) (administrative law judge may consider amount of time separating studies).

Nor is there merit to Employer’s argument that the administrative law judge improperly based her finding of total disability at 20 C.F.R. §718.204(b)(2)(ii) “solely on counting heads.” Employer’s Brief at 8-9. Contrary to Employer’s characterization, the administrative law judge considered the validity of the blood gas studies, the date each was conducted, and whether they were conducted at rest or during exercise, in addition to the number of qualifying and non-qualifying studies. Decision and Order at 11-13. She permissibly found exercise blood gas studies are more probative than resting studies in determining whether Claimant is totally disabled, as they are a better predictor of his ability to work in the mines. See Coen v. Director, OWCP, 7 BLR 1-30, 1-31-32 (1984); Sturnick v. Consolidation Coal Co., 2 BLR 1-972, 1-977 (1980); Id. at 12. As the administrative law judge fully explained her rationale in weighing the blood gas study evidence, we reject Employer’s assertion that she substituted her own opinion for those of the medical experts. We therefore affirm the administrative law judge’s finding that the preponderance of blood gas studies establish total disability at 20 C.F.R. §718.204(b)(2)(ii). See Compton v. Island Creek Coal Co., 211 F.3d 203, 207-208 (4th Cir. 2000); Decision and Order at 13.

The administrative law judge next considered the opinions of Drs. Nader, Green, Mabe, Zaldivar, and Rosenberg.9 Decision and Order at 14-23; Director’s Exhibit 13;

9
We affirm, as unchallenged, the administrative law judge’s finding that Claimant’s usual coal mine work required heavy labor. See Skrack, 6 BLR at 1-711; Decision and Order at 4.

5
Claimant’s Exhibits 2, 3; Employer’s Exhibits 1, 2, 7, 8. Drs. Nader, Green, and Mabe opined that Claimant is totally disabled by hypoxemia based on his arterial blood gas results. Director’s Exhibit 13; Claimant’s Exhibits 2, 3. In contrast, Drs. Zaldivar10 and Rosenberg11 did not diagnose a totally disabling respiratory impairment. Employer’s Exhibits 1, 2, 7, 8.

The administrative law judge gave “normal probative weight” to the opinions of Drs. Nader, Green, and Mabe as reasoned, documented, and supported by the qualifying blood gas study results and an accurate understanding of Claimant’s coal mine employment and its exertional requirements. Decision and Order at 22. While noting Dr. Zaldivar’s opinion is inconsistent with her finding that the blood gas studies establish total disability, she nonetheless gave it “normal probative weight” as reasoned, documented, and based on the blood gas study he administered. Id. at 22. In contrast, she found Dr. Rosenberg’s opinion entitled to little probative weight because it was based on a misinterpretation of the regulations and was contrary to her finding that the blood gas study evidence overall supported total disability. Id. Thus, she concluded the medical opinion evidence supports a finding of total disability. 20 C.F.R. §718.204(b)(2)(iv); Decision and Order at 22-23. Finally, weighing all of the relevant evidence together, the administrative law judge found Claimant established total disability by a preponderance of the evidence pursuant to 20 C.F.R. §718.204(b)(2). Id. at 23.

We reject Employer’s assertion that the administrative law judge erred in discrediting Dr. Rosenberg’s opinion. Employer’s Brief at 17-19. Relying on Dr. Zaldivar’s most recent study, Dr. Rosenberg opined that Claimant’s blood gas studies are “preserved and non-qualifying.” Employer’s Exhibits 2, 8 at 19. He stated Claimant has a mild reduction of gas exchange overall, considering age and altitude, and does not have any real significant changes in gas exchange with exercise. Employer’s Exhibit 8 at 15-

10
Relying on the results of the blood gas study he administered over those performed at Norton Community Hospital, Dr. Zaldivar opined that Claimant has the respiratory capacity to perform his last coal mine work. He attributed Claimant’s shortness of breath to his previous heart attack and poor physical conditioning. Employer’s Exhibits 1, 7 at 33-35.
11
Dr. Rosenberg opined that Claimant’s gas exchange is normal and he retains the pulmonary and respiratory ability to return to his previous coal mine work. Employer’s Exhibits 2, 8 at 18. While acknowledging some of Claimant’s “older” blood gas results were qualifying, Dr. Rosenberg relied on Dr. Zaldivar’s study because it was the most recent and “probably the most valid representation.” Employer’s Exhibit 8 at 19.
6

16. Dr. Rosenberg opined that any exercise limitation was due to poor conditioning or
    cardiac problems. Id. at 27.

    The administrative law judge noted Dr. Rosenberg relied on Dr. Zaldivar’s 2019
    

    non-qualifying blood gas study based, in part, on its recency. Decision and Order at 22; Employer’s Exhibits 2, 8 at 19. She found his conclusion that Claimant’s blood gases were “preserved and non-qualifying,” while true for Dr. Zaldivar’s study, was inconsistent with the blood gas study results of record, which were preponderantly qualifying for total disability. Id. The administrative law judge further found in opining that Claimant’s gas exchange is normal, “Dr. Rosenberg’s conclusion appears to be based, at least in part, on a misinterpretation of the regulations,” as well as his applying a “correcting” equation to the results of Dr. Zaldivar’s 2019 blood gas study.12 Decision and Order at 22. Thus, contrary to Employer’s assertion, the administrative law judge did not discount Dr. Rosenberg’s opinion because he considered Claimant’s age in interpreting his blood gas study results. Rather, she found Dr. Rosenberg’s opinion that Claimant’s blood gases were preserved and non-qualifying to be inconsistent with the blood gas study results of record and his misunderstanding of the regulations. Id. She therefore permissibly found Dr. Rosenberg’s opinion is not well-reasoned to the extent that he concluded the non-qualifying blood gas studies demonstrate Claimant is not totally disabled, contrary to her finding the blood gas study evidence as a whole supports a finding of total disability. See Milburn Colliery Co. v. Hicks, 138 F.3d 524, 533 (4th Cir. 1998); Sterling Smokeless Coal Co. v. Akers, 131 F.3d 438, 441 (4th Cir. 1997).

    Nor is there merit to Employer’s argument that the opinions of Drs. Nader, Green,
    and Mabe are not reasoned or credible because they did not review the “totality” of Claimant’s blood gas study results. Employer’s Brief at 14-17. Dr. Nader stated Claimant’s objective testing reflected a “mild decrease in diffusion capacity” and

    12
    Dr. Rosenberg stated “the [Department of Labor] tables for qualifying [blood gas
    study] impairment are outlined only up to age [seventy-one]” and Claimant was seventy- nine years of age when the January 9, 2019 exercise study was performed. Employer’s Exhibit 2. Dr. Rosenberg explained that “utilizing the portion of [the] Crapo equation for age decrement . . . and applying this correction factor and the age differential of eight years, qualifying gas exchange is determined by reducing 100 mm Hg by 3.43 mm Hg. . .” Id. (computations omitted). The administrative law judge correctly noted the Appendix C tables only account for the altitude of the testing site and a miner’s PO2 and PCO2 levels. Id., citing 20 C.F.R. Part 718, Appendix C. She then reasonably determined Dr. Rosenberg conflated the Appendix C blood gas study tables with the tables used to determine the qualifying values of a pulmonary function test, found in Appendix B, which account for the miner’s age. See Underwood v. Elkay Mining, Inc., 105 F.3d 946, 949 (4th Cir. 1997); Decision and Order at 22 n.16, citing 20 C.F.R. Part 718, Appendix B.
    7
    “significant hypoxemia” based on Claimant’s resting blood gas study and his history of shortness of breath upon exertion, chronic cough, wheezing, and sputum expectoration. Director’s Exhibit 13. She opined that Claimant could not perform the requirements of his previous coal mine employment on the basis of his hypoxemia. Id. Similarly, Dr. Green noted Claimant had daily wheezing and coughing, and exertional shortness of breath for years, worsening over the past five years. Claimant’s Exhibit 2. He opined that based on Claimant’s objective testing, he remains totally disabled from a pulmonary capacity standpoint due to his exercise hypoxemia, and it would be “harmful for [Claimant] to return to his previous coal mine employment” and “perform heavy labor in the setting of his hypoxemia.” Id. Dr. Mabe opined that Claimant’s objective testing reflected exertional hypoxemia with dyspnea on exertion, daily cough, and sputum production. Claimant’s Exhibit 3. He also opined that Claimant is totally disabled from a pulmonary capacity and could not perform the exertional requirements of his last coal mine employment of lifting fifty to one hundred pounds at any given time. Id.

    The administrative law judge permissibly found the opinions of Drs. Nader, Green,
    and Mabe that Claimant lacks the pulmonary capacity to perform his coal mine employment are well-reasoned and documented. She found their opinions to be supported by the objective testing they conducted, an accurate understanding of Claimant’s employment and its exertional requirements, and the results of the preponderance of the blood gas studies. See Hicks, 138 F.3d at 533; Akers, 131 F.3d at 441; Decision and Order at 21; Director’s Exhibit 13; Claimant’s Exhibits 2, 3. As the administrative law judge provided valid rationales for her credibility determinations regarding the medical opinion evidence, we reject Employer’s assertion that she “resorted to counting heads” and “reli[ed] on mere numbers alone.”13 Employer’s Brief at 19. We therefore affirm her finding that the preponderance of the medical opinions establish total disability at 20 C.F.R.
    §718.204(b)(2)(iv).

    In addition, we reject Employer’s argument that the administrative law judge failed
    to explain her review of the evidence as a whole. Employer’s Brief at 19-20. Having found the blood gas studies support a finding of total disability, the administrative law judge considered whether they were outweighed by any contrary probative evidence. Decision and Order at 23. As discussed above, she permissibly found the medical opinion evidence supports a finding of total disability and does not constitute contrary probative evidence that would undermine the qualifying blood gas studies. She also considered the non- qualifying pulmonary function studies but permissibly found they do not undermine the

    13
    Contrary to Employer’s assertion, the administrative law judge did not find the
    opinions of Drs. Nader, Green, and Mabe “conclusory” on the issue of total respiratory disability. Employer’s Brief at 16.

                                         8
    

    qualifying blood gas studies. See Sheranko v. Jones & Laughlin Steel Corp., 6 BLR 1-797, 1-798 (1984) (blood gas studies and pulmonary function studies measure different types of impairment); Decision and Order at 23. We therefore affirm her determination that Claimant established total disability at 20 C.F.R. §718.204(b) by a preponderance of the evidence considered as a whole.

                 Rebuttal of the Section 411(c)(4) Presumption
    

    Because Claimant invoked the Section 411(c)(4) presumption, the burden shifted to
    Employer to establish he has neither legal nor clinical pneumoconiosis, or “no part of [his] respiratory or pulmonary total disability was caused by pneumoconiosis as defined in [20 C.F.R.] § 718.201.” 20 C.F.R. §718.305(d)(1)(i), (ii). The administrative law judge found Employer failed to establish rebuttal by either method.

                             Legal Pneumoconiosis
    

    After finding Employer disproved clinical pneumoconiosis, the administrative law
    judge addressed legal pneumoconiosis.14 Decision and Order at 30. To disprove legal pneumoconiosis, Employer must establish Claimant does not have a chronic lung disease or impairment “significantly related to, or substantially aggravated by, dust exposure in coal mine employment.” 20 C.F.R. §§718.201(a)(2),(b), 718.305(d)(1)(i)(A); see Minich v. Keystone Coal Mining Corp., 25 BLR 1-149, 1-155 n.8 (2015) (Boggs, J., concurring and dissenting).

    The administrative law judge considered the opinions of Drs. Zaldivar and
    Rosenberg that Claimant does not have legal pneumoconiosis.15 She found their opinions insufficient to rebut the existence of legal pneumoconiosis because neither physician diagnosed a pulmonary or respiratory impairment, contrary to her determination that Claimant has a totally disabling pulmonary or respiratory impairment. Decision and Order at 32-33. She also determined Drs. Zaldivar and Rosenberg did not adequately explain why coal dust exposure was not a contributing cause of any respiratory or pulmonary condition affecting Claimant. Id. at 33. The administrative law judge therefore concluded

    14
    “Legal pneumoconiosis” includes any chronic lung disease or impairment and its
    sequelae arising out of coal mine employment. 20 C.F.R. §718.201(a)(2).
    15
    The administrative law judge also considered the opinions of Drs. Nader, Green,
    and Mabe that Claimant has legal pneumoconiosis. Decision and Order at 30-31; Director’s Exhibit 13; Claimant’s Exhibits 2, 3. She found these opinions cannot aid Employer in rebutting the existence of legal pneumoconiosis. Decision and Order at 31.
    9
    the medical opinions of Employer’s experts did not rebut the presumed existence of legal pneumoconiosis. Id.

    Employer alleges the administrative law judge did not properly weigh Dr. Zaldivar’s
    opinion. Employer’s Brief at 22-23. We disagree. She permissibly found that although Dr. Zaldivar diagnosed a “mild restriction of total lung capacity with mild diffusion abnormality,” he did not “offer[] any explanation as to its etiology or clarif[y] why this mild impairment is not related to coal mine dust exposure.” Decision and Order at 32; see Harman Mining Co. v. Director, OWCP [Looney], 678 F.3d 305, 313-14 (4th Cir. 2012) (an administrative law judge may accord less weight to a physician who fails to adequately explain why a miner’s obstructive disease “was not due at least in part to his coal dust exposure”). The administrative law judge therefore rationally determined Employer did not disprove the existence of legal pneumoconiosis with Dr. Zaldivar’s opinion. See Minich, 25 BLR at 1-159.

    Employer next argues the administrative law judge applied an incorrect legal
    standard by requiring Dr. Rosenberg to identify the cause of the blood gas abnormality he diagnosed in addition to establishing the abnormality did not meet the definition of legal pneumoconiosis. Employer’s Brief at 24-25, referencing Decision and Order at 32. We disagree. The administrative law judge correctly stated Employer has the burden of establishing Claimant does not have legal pneumoconiosis, i.e., a chronic lung disease or impairment significantly related to, or substantially aggravated by, dust exposure in coal mine employment. Decision and Order at 30, citing 20 C.F.R. §718.201(a)(2), (b). Contrary to Employer’s argument, she did not apply an inappropriate standard in rejecting Dr. Rosenberg’s opinion. Employer’s Brief at 24. Rather, she permissibly found Dr. Rosenberg’s opinion entitled to little weight because even if he is correct that Claimant’s cardiac condition caused or contributed to his abnormal blood gas results, he did not explain why coal dust exposure did not also contribute, in part, to that impairment, especially considering the length of Claimant’s coal mine employment. Decision and Order at 33; see Looney, 678 F.3d at 313-14; Decision and Order at 33.

    It is for the administrative law judge to assess the credibility of the evidence and to
    determine how much weight to assign it. See W. Va. CWP Fund v. Bender, 782 F.3d 129, 144-45 (4th Cir. 2015). Because she permissibly discredited the opinions of Drs. Zaldivar and Rosenberg, the only opinions supportive of a finding that Claimant does not have legal pneumoconiosis,16 we affirm the administrative law judge’s finding that Employer failed

    16
    Because Employer bears the burden to prove Claimant does not have
    pneumoconiosis, we need not address its arguments regarding the weight the administrative
    10
    to rebut the Section 411(c)(4) presumption by disproving the existence of pneumoconiosis.17 20 C.F.R. §718.305(d)(1)(i).

                              Disability Causation
    
    The administrative law judge next addressed whether Employer established that no
    

    part of Claimant’s respiratory or pulmonary disability was caused by pneumoconiosis. 20 C.F.R. §718.305(d)(1)(ii); Decision and Order at 33-34. Employer alleges the administrative law judge’s errors in weighing the evidence relevant to legal pneumoconiosis caused her to err in finding Employer did not rebut disability causation. Employer’s Brief at 25. We disagree.

    The administrative law judge rationally discounted the opinions of Drs. Zaldivar
    

    and Rosenberg on the cause of Claimant’s respiratory disability because neither physician diagnosed legal pneumoconiosis, contrary to her finding that Employer failed to disprove the existence of the disease. See Hobet Mining, LLC v. Epling, 783 F.3d 498, 505 (4th Cir. 2015); Big Branch Res., Inc. v. Ogle, 737 F.3d 1063, 1074 (6th Cir. 2013); Decision and Order at 33-34. We therefore affirm the administrative law judge’s finding that Employer failed to establish no part of Claimant’s total disability was caused by pneumoconiosis. 20 C.F.R. §718.305(d)(1)(ii); Decision and Order at 34.

law judge accorded to the opinions of Drs. Nader, Green, and Mabe that Claimant has legal pneumoconiosis. See 20 C.F.R. §718.305(d)(1)(i).
17
Because the administrative law judge provided valid reasons for discrediting the opinions of Drs. Zaldivar and Rosenberg on the issue of legal pneumoconiosis, we need not address Employer’s remaining arguments regarding the weight accorded to their opinions. See Kozele v. Rochester & Pittsburgh Coal Co., 6 BLR 1-378, 1-382 n.4 (1983).
11
Accordingly, the administrative law judge’s Decision and Order Awarding Benefits is affirmed.

SO ORDERED.

JUDITH S. BOGGS, Chief
Administrative Appeals Judge

GREG J. BUZZARD
Administrative Appeals Judge

DANIEL T. GRESH
Administrative Appeals Judge