                              In the

    United States Court of Appeals
                For the Seventh Circuit
                    ____________________
No. 18-2097
CONSOLIDATION COAL COMPANY,
                                                        Petitioner,
                                v.

DIRECTOR, OFFICE OF WORKERS’ COMPENSATION PROGRAMS,
UNITED STATES DEPARTMENT OF LABOR,
                                          Respondent.
                    ____________________

               Petition for Review of an Order of the
                       Benefits Review Board.
                          No. 17-BLA-0351.
                    ____________________

 ARGUED NOVEMBER 29, 2018 — DECIDED DECEMBER 21, 2018
               ____________________

   Before FLAUM, RIPPLE, and MANION, Circuit Judges.
    FLAUM, Circuit Judge. Ralph Ross worked as a coal miner
for approximately thirty years. He smoked cigarettes for al-
most as long but was able to quit after his first heart attack.
Ross continued to work as a coal miner even though he suf-
fered another heart attack and had diﬃculty breathing at
work. Approximately six years after Ross stopped working in
the coal mines, his breathing problems became severe.
2                                                    No. 18-2097

    On January 19, 2012, Ross filed a claim for benefits under
the Black Lung Benefits Act, 30 U.S.C. § 901 et seq. At first, the
administrative law judge (“ALJ”) denied Ross’s claim. Ross
petitioned the United States Department of Labor’s Benefits
Review Board (the “Board”) for review, and the Board va-
cated and remanded the ALJ’s decision for further considera-
tion. On remand, the ALJ granted Ross’s claim. Ross’s former
employer, petitioner Consolidation Coal Company (the “Em-
ployer”), petitioned the Board for review, and the Board af-
firmed the ALJ’s subsequent decision. Then the Employer
filed this appeal. We enforce the decision of the Board.
                         I. Background
    A. Statutory and Regulatory Framework
    Congress passed the Black Lung Benefits Act (the “Act”)
in light of the “significant number” of coal miners who be-
came “totally disabled” from working in coal mines. 30 U.S.C.
§ 901(a). Under the Act, coal miners may receive modest mon-
etary and medical benefits to treat their pulmonary impair-
ments. See id. To establish eligibility for such benefits, a coal
miner must show: (1) he has pneumoconiosis, (2) the pneu-
moconiosis arose out of coal mine employment, (3) he is to-
tally disabled, and (4) the pneumoconiosis contributes to the
total disability. 20 C.F.R. § 725.202(d).
    The Act and its implementing regulations define pneumo-
coniosis as “a chronic dust disease of the lung and its seque-
lae, including respiratory and pulmonary impairments, aris-
ing out of coal mine employment.” 30 U.S.C. § 902(b); 20
C.F.R. § 718.201(a). And the regulations define two subcate-
gories of pneumoconiosis: “Clinical pneumoconiosis” refers
to “those diseases recognized by the medical community as
No. 18-2097                                                     3

pneumoconioses, i.e., the conditions characterized by perma-
nent deposition of substantial amounts of particulate matter
in the lungs and the fibrotic reaction of the lung tissue to that
deposition caused by dust exposure in coal mine employ-
ment.” 20 C.F.R. § 718.201(a)(1). “Legal pneumoconiosis” re-
fers to “any chronic lung disease or impairment and its seque-
lae arising out of coal mine employment. This definition in-
cludes, but is not limited to, any chronic restrictive or obstruc-
tive pulmonary disease arising out of coal mine employ-
ment.” Id. § 718.201(a)(2).
     To establish a respiratory or pulmonary impairment that
is “totally disabl[ing]” and qualifies him for benefits under the
Act, a miner must show that the impairment prevents him
from performing his usual coal mine work and from engaging
in gainful employment that requires similar skills to his coal
mining job and that is near his home. Id. § 718.204(b)(1)(i)–(ii).
Additionally, the coal miner must satisfy certain medical cri-
teria. Id. § 718.204(b)(2). “In absence of contrary probative ev-
idence,” evidence that meets any of the standards outlined in
§ 718.204(b)(2)(i)–(iv) “shall establish a miner’s total disabil-
ity.” Id. Under subparagraph (i), pulmonary function tests
“showing values equal to or less than those listed in [certain
tables in] Appendix B to this part for … the FEV1 test” qualify
“if, in addition, such tests also reveal the values … equal to or
less than those listed in … Appendix B for this part, for … the
FVC test, or … the MVV test, or … [a] percentage of 55 or less
when the results of the FEV1 test are divided by the results of
the FVC test (FEV1/FVC equal to or less than 55%).” Under
subparagraph (ii), arterial blood gas tests that “show the val-
ues listed in Appendix C to this part” qualify. Under subpar-
agraph (iii), medical evidence showing the miner suﬀers from
4                                                              No. 18-2097

“cor pulmonale with right-sided congestive heart failure”
qualifies. And subparagraph (iv) provides:
        Where total disability cannot be shown under
        paragraphs (b)(2)(i), (ii), or (iii) of this section, or
        where pulmonary function tests and/or blood
        gas studies are medically contraindicated, total
        disability may nevertheless be found if a physi-
        cian exercising reasoned medical judgment,
        based on medically acceptable clinical and la-
        boratory diagnostic techniques, concludes that
        a miner’s respiratory or pulmonary condition
        prevents or prevented the miner from engaging
        in employment as described in paragraph (b)(1)
        of this section.
    Congress intended for the Act to serve a remedial purpose
and for doubts “[i]n the absence of definitive medical conclu-
sion[s]” to be resolved in the miner’s favor. S. Rep. No. 92-743,
at 2315. Accordingly, the Act includes a rebuttable presump-
tion that a miner may invoke if the miner can establish that he
has spent at least fifteen years working in a coal mine and es-
tablish pursuant to § 718.204 that he suﬀers from a totally dis-
abling respiratory or pulmonary impairment.1 See 30 U.S.C.
§ 921(c)(4); 20 C.F.R. § 718.305. If the miner can make that
showing, the miner is presumed to be totally disabled by

    1 Congress originally added the fifteen-year presumption in 1972, see
Pub. L. No. 92–303, § 4(c) (1972); but in 1981, Congress limited its applica-
bility to claims filed before January 1, 1982, see Pub. L. No. 97–119,
§ 202(b)(1) (1981). Then, in 2010, Congress made the fifteen-year presump-
tion available for claims filed after January 1, 2005 that were still pending
on or after March 23, 2010. See Keene v. Consolidation Coal Co., 645 F.3d 844,
847 (7th Cir. 2011).
No. 18-2097                                                    5

pneumoconiosis. 20 C.F.R. § 718.305(c)(1). The miner’s em-
ployer may rebut that presumption either by disproving the
existence of legal and clinical pneumoconiosis, or by ruling
out pneumoconiosis as a partial cause of the miner’s disabil-
ity. Id. § 718.305(d)(1).
   B. Factual Background
    Ross spent thirteen years working underground in the
mine and at least seventeen years working on the surface of
the mine. Throughout his career, the dust from the mine was
inescapable. After a day’s work, his clothes were “too nasty”
to take inside his home, so he would shower at work, change
into diﬀerent clothes, and leave his work clothes hanging in
his garage. Cleaning his work clothes required using the laun-
dromat’s special washer for coal miner’s clothes, and even
then, it took two wash cycles to remove the dust and grease
from the coal mine.
    Starting at the age of twenty and for approximately the
next thirty years, Ross smoked between one-half to two packs
of cigarettes per day, though sometimes he would begin
smoking a cigarette, but would be too busy with work to fin-
ish it, so he’d extinguish it and go back to work. He quit smok-
ing in 1989 after suﬀering his first heart attack. Unfortunately,
Ross had another serious heart attack in 1995, and he suspects
he had a third heart attack in 1998.
    Ross had breathing problems while working in the coal
mines. He struggled to carry his tools while climbing the
stairs and he often had to take breaks to catch his breath. And
yet, Ross kept working. That is, he kept working until his em-
ployer “let [him] go” in 2000 because he “got blinded in the
right eye.” At that time, Ross said he felt he could still do his
6                                                 No. 18-2097

job from a cardiac standpoint and that from a pulmonary
standpoint, he “was trying.” Since his coal mining career
ended, Ross has not held steady employment. To stay busy,
Ross volunteered by cutting firewood with a chainsaw, mow-
ing lawns with a riding lawnmower, and putting up hay with
a square baler.
    Ross said his breathing problems became severe in 2006 or
2007. He has testified that since that time, he cannot walk
around his house and yard like he used to, and it takes him
longer to complete daily tasks, namely feeding his animals
and mowing the lawn. Although he takes medication for his
breathing problems, he can only perform fifteen to twenty
minutes of work before he has to sit down to take a break for
thirty-five to forty minutes. Ross uses an oxygen monitor to
make sure his oxygen does not fall so low as to risk stroke or
death. When his oxygen levels get too low, Ross uses supple-
mental oxygen.
    C. Procedural Background
      1. The ALJ’s First Decision
   On January 19, 2012, Ross filed a claim for benefits under
the Act. The District Director awarded Ross benefits in Octo-
ber 2012; the Employer requested a hearing before the Oﬃce
of Administrative Law Judges. In preparation for that hear-
ing, the Director of the Oﬃce of Workers’ Compensation Pro-
grams in the United States Department of Labor (the “Direc-
tor”), Ross, and the Employer gathered medical evidence to
present to the ALJ. The hearing occurred on October 23, 2013;
Ross and his wife both testified. After the hearing, Ross and
No. 18-2097                                                   7

the Employer submitted briefs and the ALJ issued a decision
denying benefits on September 8, 2014.
    The ALJ determined that Ross had over fifteen years of
qualifying coal mine employment, and in turn, focused on
whether Ross was entitled to invoke the fifteen-year pre-
sumption by establishing a totally disabling respiratory or
pulmonary impairment using qualifying medical evidence.
Beginning with the pulmonary function tests, the ALJ noted
that the parties submitted three such exams for Ross. Dr. Taz-
baz, on behalf of the Department of Labor, performed the first
exam on Ross on February 13, 2012, and that exam produced
qualifying values prebronchodilator. Dr. Tuteur, on behalf of
the Employer, performed two more exams on Ross on June
28, 2012, and those exams produced nonqualifying values
prebronchodilator and postbronchodilator. Since the ALJ
found the more recent results to be the best indicator of Ross’s
pulmonary condition, the ALJ concluded that the pulmonary
function testing, standing alone, did not support a finding of
total disability under 20 C.F.R. § 718.204(b)(2)(i).
    Then, the ALJ discussed the blood gas studies: Ross un-
derwent four such studies, two at rest and two after exercise.
In both “after exercise” studies, Ross’s PCO2 increased and his
PO2 decreased, thereby producing qualifying values. The ALJ
noted that Dr. Tazbaz concluded that these studies showed
that Ross had a “pulmonary limitation to exercise with hy-
poxemia that requires oxygen,” and that Dr. Tuteur indicated
that the “after exercise” qualifying result was abnormal, but a
reflection of a development of oxygen gas exchange impair-
ment after exercise. The ALJ found that the blood gas studies,
standing alone, supported a finding of total disability under
§ 718.204(b)(2)(ii).
8                                                            No. 18-2097

    Next, the ALJ briefly noted that there was no evidence that
Ross had cor pulmonale with right-sided congestive heart
failure, so total disability could not be supported on that basis.
See id. § 718.204(b)(2)(iii).
    Finally, the ALJ considered the medical opinion evidence
of three doctors. First, Dr. Tazbaz opined that Ross was “se-
verely impaired with desaturation on exercise test” and “can-
not do his activities in last year of employment.” He diag-
nosed Ross with chronic obstructive pulmonary disease, coal
workers’ pneumoconiosis, coronary artery disease, and hy-
poxemia with exercise. He opined that the cause of these con-
ditions was exposure to coal mine dust and cigarette smoke.
Second, Dr. Tuteur indicated that Ross had a “minimal ob-
structive abnormality and some air trapping,” but he opined
that this was “not clinically meaningful and … is [in] no way
associated with any disability or reduced function.” Dr. Tu-
teur explained that Ross’s hypoxemia and blood gas results
were “most likely … due to a right to left intracardiac shunt
unrelated to the inhalation of coal mine dust, but consistent
with complications of the coronary artery disease, myocardial
infarctions, surgical treatment and their sequelae.”2 And Dr.
Tuteur opined that there was no evidence to support legal or
clinical coal workers’ pneumoconiosis or any coal-mine-dust-
related pulmonary process. Finally, Dr. Selby reviewed Ross’s
medical records and submitted a report of his findings. In that
report, dated March 18, 2013, Dr. Selby opined that Ross was


    2 The ALJ also noted that Dr. Tuteur testified at a deposition that even

when Ross received 100% oxygen during an exam, Ross’s hypoxemia was
not corrected, which Dr. Tuteur interpreted as an indication that: (1)
Ross’s blood never gets to his lungs because it is shunted away, and (2)
the cause of Ross’s hypoxemia was not a pulmonary condition.
No. 18-2097                                                   9

not totally disabled from a pulmonary or respiratory stand-
point. Dr. Selby also testified at a deposition on September 10,
2013: In his opinion, Ross’s minor pulmonary impairment
was due to his extensive cigarette smoking and prior history
of histoplasmosis or tuberculosis. He explained that Ross’s
post-exercise levels demonstrated serious hypoxia, which
“might cause some limitation.” But Dr. Selby testified that the
cause of Ross’s drop in oxygen was not pulmonary in nature
because his pulmonary function tests were normal, which “is
virtually 100 percent predictive of no lung disease.” He testi-
fied that the evidence is “exactly to the contrary” of a finding
of total disability due to a pulmonary condition.
   The ALJ summarized the medical opinion evidence, in rel-
evant part, as follows:
       All three physicians are board-certified in pul-
       monary and internal medicine, and only one
       physician, Dr. Tazbaz, opined that [Ross] was
       totally disabled from a pulmonary standpoint.
       Dr. Tuteur opined that [Ross] was totally disa-
       bled from a cardiac standpoint, and Dr. Selby
       did not find that [Ross] was totally disabled at
       all. With regard to the issue of total disability,
       Drs. Selby and Tuteur’s opinions were well rea-
       soned, documented, and supported by the total-
       ity of the medical evidence. Dr. Tazbaz’s very
       minimal opinion did not consider [Ross’s] other
       testing and medical evidence, or [Ross’s] severe
       cardiac issues as … potential causes of his im-
       pairment. Greater weight may be accorded an
       opinion supported by more extensive documen-
       tation over an opinion supported by limited
10                                                          No. 18-2097

         medical data…. Accordingly, I find Dr. Tazbaz’s
         opinion is entitled to less weight and it is not
         suﬃciently documented. A doctor’s opinion
         that is both reasoned and documented and is
         supported by objective medical tests and con-
         sistent with all the documentation in the record,
         is entitled to greater probative weight…. There-
         fore, based on the abovementioned discussion, I
         find that the medical opinion evidence, stand-
         ing alone, does not support a finding of total
         disability. [See id. § 718.204(b)(2)(iv).]
    Then, the ALJ considered all the probative evidence and
found that the preponderance of the evidence did not estab-
lish that Ross had a totally disabling respiratory or pulmo-
nary impairment. As a result, the ALJ concluded that Ross
was not entitled to invoke the fifteen-year presumption. Ulti-
mately, the ALJ denied Ross’s claim for benefits.3
         2. The First Petition for Review
    Ross petitioned the Board to review the ALJ’s decision.
The Director filed a response, asking the Board to vacate the
denial of benefits and to remand the case for further consid-
eration. The Employer also filed a response, and it moved to
strike the Director’s brief as violating 20 C.F.R. § 802.212(b),
which limits the Board’s consideration of arguments in re-
sponse briefs to those that respond to arguments raised in the



     3The ALJ also found that Ross did not establish the existence of com-
plicated pneumoconiosis such that he would be entitled to invoke the ir-
rebuttable presumption under 30 U.S.C. § 921(c)(3) and 20 C.F.R.
§ 718.304(a). Those findings are not at issue on appeal.
No. 18-2097                                                    11

petitioner’s brief or that support the decision below; the Board
denied the motion.
    As for the merits of the appeal, the Board determined that
the ALJ erred in several ways: combining the analysis of total
disability and disability causation, which are meant to be dis-
tinct inquiries; characterizing Dr. Tazbaz’s opinion as not con-
sidering Ross’s severe cardiac issues as potential causes of the
impairment when in fact Dr. Tazbaz considered Ross’s aortic
valve replacement and triple bypass surgery, questioned the
congestive heart failure diagnosis, performed an electrocardi-
ogram that produced normal sinus rhythm, and diagnosed
Ross with coronary artery disease; considering Dr. Tazbaz’s
opinion to not be “suﬃciently documented” when Dr. Tazbaz
relied on results from a physical examination, chest x-ray,
pulmonary function study, blood gas study, echocardiogram
(ECG), and Ross’s smoking, work, and surgery histories; and
not explaining why Drs. Tuteur’s and Selby’s opinions were
better supported, especially in light of the fact that Ross’s
treatment records did not show a shunt despite extensive car-
diac testing, Dr. Tuteur did not include the complete results
of Ross’s blood gas study conducted with 100% oxygen, and
neither doctor conducted an ECG. Due to these errors, the
Board vacated the ALJ’s findings that Ross did not establish
total disability under 20 C.F.R. § 718.204(b)(2)(iv), that the to-
tality of the evidence did not establish total disability under
§ 718.204(b)(2), and that Ross did not invoke the fifteen-year
presumption under 30 U.S.C. § 921(c)(4). As such, the Board
remanded the case to the ALJ for further consideration of the
relevant evidence.
   The Employer moved for reconsideration of the Board’s
decision, arguing that the Board erred in denying the motion
12                                                  No. 18-2097

to strike the Director’s brief and that the Board exceeded its
scope of review by engaging in a de novo review of the case,
improperly adopting the Director’s position, and usurping
the ALJ’s fact-finding authority. The Board denied the Em-
ployer’s motion.
       3. The ALJ’s Second Decision
    Back before the ALJ, the Employer moved for leave to sub-
mit supplemental medical opinions. The ALJ granted that mo-
tion and it admitted the Employer’s submission of supple-
mental medical opinions from Drs. Tuteur and Selby. After
further briefing, Ross submitted Dr. Tazbaz’s supplemental
opinion and additional treatment records, and the Employer
submitted second supplemental opinions by Drs. Tuteur and
Selby. The ALJ issued its second decision on March 7, 2017.
The ALJ incorporated the findings from his first decision un-
der 20 C.F.R. § 718.204(b)(iv), and then outlined, in detail, the
supplemental medical opinion evidence.
    In Dr. Tuteur’s March 18, 2016 supplemental opinion, he
included the complete results of the blood gas study that was
conducted on June 28, 2012, on which Dr. Tuteur heavily re-
lied in reaching his first opinion that a right-to-left shunt
caused Ross’s hypoxemia. In this specific exam, Ross received
100% oxygen and still experienced hypoxemia. In the supple-
mental opinion, Dr. Tuteur found that it was unequivocally
clear that Ross was totally and permanently disabled from en-
gaging in work as a coal miner and that the disability is due
to the demonstrated pathophysiology where Ross becomes
hypoxemic with exercise. But Dr. Tuteur confirmed that the
physiologic presence of a right-to-left shunt was well-docu-
mented in the pulmonary function test he performed on Ross
in 2012. He acknowledged that performing a bubble study at
No. 18-2097                                                 13

the time of an echocardiogram is a less sensitive method of
confirming the presence of a right-to-left shunt, and that this
test was not done. Nevertheless, Dr. Tuteur still concluded
with reasonable medical certainty that because Ross has ad-
vanced chronic coronary artery disease and very mild chronic
obstructive pulmonary disease, the exercise-induced oxygen
desaturation was a result of a right-to-left shunt. He empha-
sized that Ross does not have a meaningful impairment of
ventilatory function, nor does he have a meaningful impair-
ment of oxygen gas exchange due to a primary pulmonary
process. He also stated that the cardiac disease is in no way
related to, aggravated by, or caused by inhalation of coal mine
dust or the development of coal workers’ pneumoconiosis.
    Dr. Selby submitted his supplemental opinion on May 13,
2016. He explained that the 100% oxygen test Dr. Tuteur per-
formed showed incontrovertible proof of the presence of a
shunt and that the decreased PO2 was not due to lung disease.
Citing a New England Journal of Medicine article from 1984
describing the use of diﬀusing capacity as a predictor of arte-
rial oxygen desaturation during exercise in patients with
chronic obstructive pulmonary disease, Dr. Selby explained
that the study showed that if a patient had a diﬀusion capacity
above 55% of predicted, virtually 100% of the time the exer-
cise blood gases would show no desaturation of oxygen. He
noted that Ross had a normal diﬀusion capacity when cor-
rected for alveolar volume, but that even the obtained raw
value was further support that the oxygen drop could not be
caused by pulmonary disease and that another source must
be the cause. Finally, Dr. Selby disagreed with Dr. Tuteur’s
diagnosis of a minimal obstructive ventilatory defect. He reit-
erated his earlier opinion that Ross’s condition is not a total
14                                                No. 18-2097

and permanent disability, and that Ross does not have clinical
or legal pneumoconiosis.
    Dr. Tazbaz based his August 3, 2016 supplemental opinion
on his first opinion and a review of additional medical opin-
ions and treatment records. He observed that x-rays and a CT
scan from 2012 established pneumoconiosis radiologically.
Dr. Tazbaz diagnosed Ross with clinical pneumoconiosis
caused by inhalation of coal mine dust, chronic obstructive
pulmonary disease caused by coal mine dust and cigarette
smoking, and total disability due to pneumoconiosis and
chronic obstructive pulmonary disease. He further opined
that Ross’s obesity and aging added to his disability. Regard-
ing the study Dr. Selby cited, Dr. Tazbaz observed that the
study did not address the subset of patients who had com-
bined chronic obstructive pulmonary disease, coal workers’
pneumoconiosis, obesity, and aging as risk factors for oxygen
desaturation, and that those patients (including Ross) are
more likely to desaturate with all of those factors combined.
Next, Dr. Tazbaz noted that Ross’s stress test from August 2,
2013 did not show cardiac ischemia, which would mean that
the bypass from Ross’s coronary artery bypass graft surgery
was functioning well, and that the oxygen desaturation could
not be attributed to heart disease. Similarly, an echocardio-
gram performed on February 1, 2012 showed normal heart
function and therefore, Ross did not have heart failure. Based
on this medical evidence, Dr. Tazbaz opined that Ross’s heart
disease had been treated surgically and was not causing any
major issues from a cardiac standpoint. And Dr. Tazbaz main-
tained that the test of choice to determine the presence of a
shunt is an echocardiogram with a bubble study, which was
not done here.
No. 18-2097                                                   15

    After reviewing Dr. Tazbaz’s supplemental opinion and
the results of the stress test and echocardiogram, Dr. Tuteur
submitted a second supplemental opinion. He confirmed that
his previous opinion was unchanged, and he added that there
was no meaningful obstructive ventilatory abnormality,
meaning that there was no chronic obstructive pulmonary
disease. He again confirmed that the echocardiogram did not
use a bubble study to determine whether a shunt was present;
he noted that the echocardiogram “did demonstrate low nor-
mal left ventricular ejection fraction,” but that no comment
was made regarding an assessment of diastolic dysfunction,
which is “a particularly important factor especially in the face
of sub-optimally controlled hypertension.” He also remarked
that “[n]o comment was made on the state of function of the
aortic valve replacement.” Finally, Dr. Tuteur refuted Dr. Taz-
baz’s conclusion that Ross has clinical pneumoconiosis, ex-
plaining that the x-rays were mostly negative and that the di-
agnosis was unconfirmed by CT scan. He also disagreed with
Dr. Tazbaz’s diagnosis of legal pneumoconiosis because he
concluded there was clinically no meaningful airflow obstruc-
tion by pulmonary function testing.
    Dr. Selby also submitted a second supplemental opinion
after reviewing the stress test, the echocardiogram, Dr. Taz-
baz’s supplemental opinion, and Dr. Tuteur’s second supple-
mental opinion. Dr. Selby agreed with Dr. Tazbaz that there
was no significant reversibility in Ross’s FEVl/FVC ratio, but
Dr. Selby stated that the normal ratio indicates that there is no
permanent obstruction. Dr. Selby also agreed with Dr. Tazbaz
that the article and study he cited did not separate all possible
comorbidities like coal workers’ pneumoconiosis or obesity.
But, he stated that obesity does not directly aﬀect diﬀusion
16                                                           No. 18-2097

capacity and that aging is already adjusted for in the pre-
dicted values. Notwithstanding the absence of a bubble study,
Dr. Selby defended his opinion that a shunt could be the only
cause of exercise hypoxia when there is no congestive heart
failure. In the end, he still concluded that Ross did not have
coal workers’ pneumoconiosis and that Ross’s exercise was
not significantly limited by pulmonary disease.
    Based on the further developed record of medical opinion
evidence, the ALJ concluded that Dr. Tazbaz’s opinion was
“well-documented” and “supported by the underlying objec-
tive tests and various work, smoking and medical histories.”
Next, the ALJ found that “Dr. Tuteur now opines that [Ross]
suﬀers from a totally disabling impairment which is respira-
tory or pulmonary in nature and this conclusion is supported
by his interpretation of the blood gas study values on exer-
cise.”4 Finally, the ALJ faulted Dr. Selby for not discussing the
significance of the exercise blood gas studies that yielded
qualifying results, and for not addressing whether Ross is


     4 Comparing the plain language of Dr. Tuteur’s supplemental opin-
ions and this part of the ALJ’s decision might suggest tension—Dr. Tuteur
makes clear he thinks the cause of Ross’s total and permanent disability is
a cardiac impairment (the shunt), not a respiratory or pulmonary impair-
ment. However, relying on the results of the exams Dr. Tuteur performed
on Ross and Dr. Tuteur’s observation that those exams produced qualify-
ing results constitute substantial evidence to support the ALJ’s finding
here. See Midland Coal Co. v. Dir., Office of Workers’ Comp. Programs, 358
F.3d 486, 493 (7th Cir. 2004) (to decide if total disability has been estab-
lished, “an ALJ must consider all relevant evidence on the issue of disabil-
ity including medical opinions which are phrased in terms of total disabil-
ity or provide a medical assessment of physical abilities or exertional lim-
itations which lead to that conclusion” (quoting Poole v. Freeman United
Coal Mining Co., 897 F.2d 888, 894 (7th Cir. 1990))).
No. 18-2097                                                 17

able to perform his usual coal mine work despite the qualify-
ing blood gas results. As such, the ALJ found Dr. Selby’s opin-
ions not well-reasoned and the ALJ accorded them “little
weight.”
    The ALJ decided that the better-reasoned opinions on total
disability were those of Drs. Tazbaz and Tuteur. And the ALJ
found that the preponderance of the medical opinions estab-
lished total disability under 20 C.F.R. § 718.204(b)(2)(iv).
Next, the ALJ considered all the evidence and found that the
preponderance of the evidence established that Ross suﬀers
from a totally disabling pulmonary impairment and cannot
return to his previous coal mine employment. Id.
§ 718.204(b)(1). Because the parties did not dispute that Ross
satisfied the requisite number of years of coal mine employ-
ment, the ALJ then concluded that Ross established condi-
tions suﬃcient to invoke the rebuttable presumption of total
disability due to pneumoconiosis under 30 U.S.C. § 921(c)(4)
and 20 C.F.R. § 718.305.
    As for rebutting the presumption, the ALJ explained that
the only medical opinion evidence that could support the Em-
ployer’s attempt to disprove the existence of legal pneumoco-
niosis were those of Drs. Tuteur and Selby. However: the ALJ
found Dr. Tuteur’s statements about Ross’s obstructive im-
pairments inconsistent; the ALJ faulted Dr. Tuteur for not ad-
dressing how he eliminated Ross’s significant coal dust expo-
sure and attributed the impairment to Ross’s smoking history
exclusively; and the ALJ took issue with Dr. Tuteur’s conclu-
sion that Ross did not have chronic obstructive pulmonary
disease despite the several years of treatment records diag-
nosing Ross with that disease and a CT scan interpretation by
18                                                  No. 18-2097

a board-certified B-reader diagnosing Ross with mild to mod-
erate centrilobular emphysema. Similarly, the ALJ found that
Dr. Selby’s opinion did not adequately consider Ross’s medi-
cal and treatment records regarding chronic obstructive pul-
monary disease and emphysema, nor did it suﬃciently ad-
dress Ross’s approximately thirty-year exposure to coal dust.
And the ALJ noted that Dr. Selby’s view that Ross’s decrease
in oxygen was not pulmonary because pulmonary function
tests are “virtually 100 percent predictive of no lung disease”
was contrary to the Act’s implementing regulations that per-
mit miners to establish a totally disabling respiratory impair-
ment by blood gas studies. Finally, the ALJ credited Dr. Taz-
baz’s qualification of the utility of Dr. Selby’s citation to the
diﬀusing capacity study as it did not consider all of Ross’s
comorbidities.
     Since the ALJ accorded the two relevant medical opinions
little weight, he concluded that there was insuﬃcient evi-
dence to disprove the presumed existence of legal pneumoco-
niosis. And because the Employer cannot rebut the presump-
tion of clinical pneumoconiosis without rebutting the pre-
sumption of legal pneumoconiosis, the ALJ reasoned that he
“need not” decide whether the Employer rebutted the exist-
ence of clinical pneumoconiosis. See 30 U.S.C. § 921(c)(4); 20
C.F.R. § 718.305(d)(1)(i). Similarly, because the ALJ held
“there [wa]s no reasoned medical opinion or other competent
evidence excluding pneumoconiosis as a causative factor in
[Ross]’s total disability,” the Employer also could not meet its
burden of proving that pneumoconiosis played no part in
Ross’s disability. 20 C.F.R. § 718.305(d)(1)(ii). Therefore, the
ALJ decided Ross was entitled to benefits under the Act.
No. 18-2097                                                   19

       4. The Second Petition for Review
    The Employer petitioned the Board to review the ALJ’s
second decision. Renewing its argument from its motion for
reconsideration, the Employer argued that the Board ex-
ceeded its scope of review by accepting the Director’s argu-
ments and vacating the ALJ’s initial decision on that basis.
The Employer also asserted that the Board directed the ALJ to
find on remand that Ross is totally disabled, in violation of the
Administrative Procedures Act (“APA”) and due process. The
Employer also took issue with the ALJ’s weighing of the med-
ical opinion evidence on the issue of total disability, arguing
this led to an erroneous finding that Ross invoked the fifteen-
year presumption. Lastly, the Employer argued that the ALJ
erred in finding that it could not rebut the presumption.
    The Board “decline[d] to consider” the Employer’s argu-
ment that the Board exceeded its scope of review because the
Board had considered and rejected the same argument in the
Employer’s motion for reconsideration. Additionally, the
Board dismissed the Employer’s argument that the Board di-
rected the ALJ to make certain findings on remand because
the plain language of the Board’s opinion stated that the ALJ
should reconsider relevant evidence. And given that the Em-
ployer had an opportunity to submit supplemental opinions
from Drs. Selby and Tuteur, as well as to file briefs to advocate
for its position, the Board found no basis for the Employer’s
assertion that the Board had violated the Employer’s due pro-
cess rights.
   The Board determined that the ALJ’s crediting of Dr. Taz-
baz’s opinion, discrediting of Dr. Selby’s opinion, and finding
that Dr. Tuteur diagnosed Ross with a totally disabling pul-
monary condition was supported by the evidence. The Board
20                                                  No. 18-2097

aﬃrmed the ALJ’s finding that the preponderance of the med-
ical evidence established total disability under 20 C.F.R.
§ 718.204(b)(2)(iv), that weighing the evidence established to-
tal disability under § 718.204(b)(2), and that Ross invoked the
presumption under 30 U.S.C. § 921(c)(4). And because only
Drs. Tuteur’s and Selby’s opinions that the shunt caused
Ross’s impairment provided rebuttal evidence, and the ALJ
did not find those opinions to be suﬃciently reasoned or doc-
umented, the Board held that the ALJ permissibly discredited
those opinions and rationally concluded that the Employer
did not carry its burden of disproving the establishment of
legal pneumoconiosis or that pneumoconiosis caused, to
some extent, Ross’s respiratory or pulmonary total disability.
    The Employer filed this appeal, seeking to strike the Direc-
tor’s response brief and to reinstate the ALJ’s first decision
denying Ross benefits under the Act.
                        II. Discussion
   On a petition for review from a decision by the Board, we
look at the ALJ’s decision and consider the entire record, but
we do not reassess the facts or substitute our judgment for
that of the ALJ. Dalton v. Oﬃce of Workers’ Comp. Programs, 738
F.3d 779, 783 (7th Cir. 2013) (citing Amax Coal Co. v. Beasley,
957 F.2d 324, 327 (7th Cir. 1992)). Our review of the Board’s
decision is limited to whether the Board exceeded its scope of
review and whether it committed an error of law. Id. (citing
Old Ben Coal Co. v. Prewitt, 755 F.2d 588, 590 (7th Cir. 1985)).
The Board’s scope of review is statutorily defined: the Board
must aﬃrm an ALJ’s decision if it is rational, supported by
No. 18-2097                                                   21

substantial evidence, and in accordance with applicable law.
Id. (citing 33 U.S.C. § 921(b)(3); 20 C.F.R. § 802.301).
   A. The Director’s Response Brief
    The Employer maintains that the Board should have
granted its motion to strike the Director’s response brief be-
cause 20 C.F.R. § 802.212(b) provides that the Board may not
consider arguments in response briefs unless the arguments
respond to issues raised in the petitioner’s brief or support the
decision below, and the Director’s response brief contained
arguments that Ross had not raised in his petition for review
from the Board and that the parties had not presented to the
ALJ. Additionally, the Employer argues that the Board vio-
lated the APA and due process by considering the Director’s
brief on the basis that the brief responded to “general allega-
tions of error” in Ross’s petition for review.
    According to the Employer, the Director’s brief criticized
the ALJ’s analysis of the medical opinion evidence “in great
detail,” while Ross’s brief only argued that because the opin-
ions of Drs. Tuteur and Selby “fail[ed] to recognize the uncon-
tradicted [blood gas] testing results as evidence of pulmonary
disability,” the ALJ erred in finding those opinions to be well-
rationalized. The Employer insists that the only area of
“agreement” between Ross’s brief and the Director’s brief is
their shared reliance on Bounds v. Marfork Coal Company, BRB
No. 13-0522, 2014 WL 3897749 (Ben. Rev. Bd. July 29, 2014)
(“Bounds II”). Even then, the Employer argues that Ross and
the Director relied on Bounds II for diﬀerent propositions.
    Ross admits that the Director’s response brief was “more
artfully stated” than his brief, but he does not concede that the
22                                                             No. 18-2097

Director advanced new arguments, in violation of the regula-
tion. Similarly, the Director claims it addressed “more fully”
the same arguments Ross made in his brief. The Director fur-
ther defends its brief by noting that there is no statutory or
regulatory rule that the response brief may only parrot an
opening brief. To the contrary, in Harris v. Todd Pacific Ship-
yards Corp., the Board interpreted “response” to include argu-
ments in agreement with the opening brief. 28 BRBS 254, 1994
WL 661158, at *3 n.4 (Ben. Rev. Bd. Oct. 25, 1994) (per curiam)
(citing 20 C.F.R. § 802.212(b)).5
    In his petition to the Board, Ross challenged the ALJ’s de-
cision that the medical evidence was insuﬃcient to show a to-
tally disabling pulmonary condition. Ross criticized the ALJ’s
jump from acknowledging that Dr. Tazbaz concluded that
Ross had a “pulmonary limitation to exercise with hypoxemia
that requires oxygen” and that two blood gas tests produced
qualifying results, to nevertheless concluding that the pre-
ponderance of the evidence established that Ross was not to-
tally disabled on a pulmonary basis. To make that jump, Ross

     5 In its reply brief, the Employer argues that Harris is “contrary to the
regulation.” We disagree. Harris’s application of the regulation was well-
reasoned. The Board in Harris denied the employers’ motions to strike be-
cause “[c]ontrary to employers’ contentions, a party may ‘respond’ to the
petitioner’s brief by agreeing with the arguments made therein, as the Di-
rector has done in the instant cases.” 1994 WL 661158, at *3 n.4. Sec-
tion 802.212(b) does not define “response,” and there is nothing in the reg-
ulation or in the plain meaning of the term “response” to suggest that a
response cannot take the form of an agreement, as Harris held. Addition-
ally, there is no indication of how similar or different a “response” must
be from the previous assertion or question, so there is support for the no-
tion that the Director could file a brief agreeing with the arguments in the
petitioner’s brief either by merely reiterating those arguments or by re-
casting those arguments in a new light.
No. 18-2097                                                   23

insisted, the ALJ must have credited Dr. Selby’s statement
that “[Ross’s] drop in [oxygen] was not pulmonary in nature.”
This was error “as a matter of black lung law” and well-settled
Board precedent, Ross contended, citing Bounds II for the
proposition that the Board had previously rejected a similar
argument that blood gas studies were cardiac-related and not
pulmonary in nature.
    In Bounds II, the miner’s claim for benefits was before the
Board for a second time. 2014 WL 3897749, at *1. On remand,
the ALJ had found that the pulmonary function study evi-
dence did not establish total respiratory disability, but that
the blood gas study and the medical opinion evidence did;
because the ALJ determined that the employer did not rebut
the presumption, the ALJ awarded the miner benefits. Id. at
*2. On appeal, the employer challenged the ALJ’s total disa-
bility finding by asserting that the blood gas study evidence
was insuﬃcient to establish total respiratory disability be-
cause the results reflected a hypertensive cardiovascular re-
sponse to exercise, not a total respiratory impairment. Id. at
*4. After noting that the ALJ based his total disability conclu-
sion on the blood gas study evidence, and that the employer’s
experts did not dispute that the blood gas studies revealed a
disabling condition, only that the blood gas studies revealed
a pulmonary condition (because they believed the studies re-
vealed a cardiac disease), the Board rejected the employer’s
argument that the blood gas study evidence was insuﬃcient
to establish a totally disabling respiratory impairment. Id.
    The Director’s brief, in relevant part, cited Bounds II after
stating that “the Director agrees with [Ross]’s assertion that
the ALJ erred by conflating the issue of total disability with
the issue of cause of disability when determining whether the
24                                                  No. 18-2097

evidence was suﬃcient to establish invocation of the
[30 U.S.C. § 921](c)(4) presumption.” The brief further states:
“As [Ross] notes, the Board has recognized that a physician’s
statement that qualifying [blood gas] results are due to non-
pulmonary causes is not relevant to the disability inquiry.…
Instead, any such opinions should be addressed when evalu-
ating the cause of disability.” The Director maintained that
the ALJ’s error was not harmless because the ALJ did not
“critically analyze the medical opinion evidence in finding no
disability,” which means that even if the presumption was in-
voked, the Board had no basis to conclude that the ALJ’s cred-
ibility findings would support a finding that the Employer
could rebut that presumption.
    What distinguishes Ross’s brief from the Director’s is that
the Director characterized the ALJ’s errors in this case and in
Bounds II as a conflation of two distinct inquiries. Ross did not
use that language, but when Ross included a block quotation
from Bounds II in his petition for review that explained the
Board’s reason for rejecting that employer’s challenge to the
suﬃciency of the miner’s qualifying blood gas studies, Ross
was making the same point as the Director: the cause of qual-
ifying blood gas results is not relevant to the ALJ’s inquiry
into whether the miner has a totally disabling pulmonary con-
dition, it is only relevant to the ALJ’s inquiry into disability
causation. Neither this distinction nor the diﬀering levels of
quality or detail between the two briefs are enough to remove
the Director’s brief from the realm of a “response” under the
regulations. 20 C.F.R. § 802.212(b); see Harris, 1994 WL 661158,
at *3 n.4.
  Finally, we are not persuaded by the Employer’s argu-
ment that the Board’s denial of the motion to strike violated
No. 18-2097                                                             25

the APA and due process. In reaching its conclusion on the
motion to strike, the Board reasoned that because Ross chal-
lenged the ALJ’s weighing of medical opinion evidence and
finding that he did not have a totally disabling pulmonary im-
pairment, the Board could consider the arguments in the Di-
rector’s brief that responded to those “general allegations of
error on that issue.” The Board cited 20 C.F.R. § 802.212(b)
and Barnes v. Director, Oﬃce of Workers’ Compensation Pro-
grams, BRB No. 93-0584, 1995 WL 80211 (Ben. Rev. Bd. Feb. 15,
1995) (en banc) to support its reasoning. The Employer inter-
prets Barnes as providing the Director with standing to argue
any issue it believes the ALJ decided erroneously so long as a
party appeals the ALJ’s decision and alleges the ALJ erred in
declining to award benefits. As such, the Employer contends
that Barnes undermines the APA and due process.6
    However, this case does not raise the concerns the Em-
ployer has about Barnes. Sitting en banc, the Board in Barnes
decided that it could consider arguments from the Director’s
brief because they “respond[ed] to claimant’s general allega-
tion that the [ALJ] erred in failing to award benefits.” 1995 WL
80211, at *2. Notably, the Board had previously held that the
claimant did not raise any arguments about the ALJ’s decision
with suﬃcient specificity to invoke the Board’s review, and
therefore, the Board refused to consider the Director’s brief as


    6 The Employer’s argument concerning an APA violation is undevel-
oped; the Employer does not identify which provision of the APA it be-
lieves was violated. As such, this argument is waived. See Shumaker v. Col-
vin, 632 F. App’x. 861, 867 (7th Cir. 2015) (undeveloped arguments on ap-
peal are waived). We will consider the Employer’s related, and more de-
veloped, argument that the Board violated due process by denying the
motion to strike.
26                                                    No. 18-2097

nonresponsive. Id. Unlike the claimant in Barnes, however,
Ross raised several specific issues in his petition for review
and the Director’s response brief only expounded on those
points. This was all in keeping with 20 C.F.R. § 802.212(b).
    Moreover, there was no due process violation because, as
Ross and the Director point out, the Employer had the oppor-
tunity to argue its case twice before the ALJ and twice before
the Board, including the chance to submit supplemental med-
ical opinion evidence. Thus, we enforce the Board’s denial of
the Employer’s motion to strike the Director’s response brief.
     B. The ALJ’s First Decision
    The Employer challenges the Board’s decision to vacate
the ALJ’s first decision and to remand the claim. Specifically,
the Employer argues that the Board blindly adopted the Di-
rector’s legal arguments and factual findings, and that the
Board forced the ALJ to do the same on remand. As such, the
Employer argues that the Board exceeded its scope of review
and that its decision was contrary to law.
    Returning to the portion of the Director’s brief that argues
the ALJ erred by conflating two distinct inquiries, the Em-
ployer now seeks to undermine this argument as relying on
conflicting Board precedent. As we discussed above, the Di-
rector cited Bounds II to support its point that the total disabil-
ity inquiry is distinct from the disability causation inquiry.
But Bounds II was not the only decision the Director cited for
that proposition; the Director also cited Street v. Dominion Coal
Corp., BRB No. 13-0116, 2013 WL 6408512 (Ben. Rev. Bd. Nov.
27, 2013) (per curiam) (“Street II”). The Employer incorrectly
argues that Bounds II reached a contrary result to Street II. Fo-
No. 18-2097                                                   27

cusing on a diﬀerent part of the Bounds II decision, the Em-
ployer now argues that the Board in Bounds II aﬃrmed the
ALJ’s consideration of the cause of the impairment before the
invocation of the fifteen-year presumption. This misstates the
relevant holding of Bounds II.
    The employer in Bounds II argued that the ALJ relieved the
miner of the burden of establishing a totally disabling respir-
atory impairment because the ALJ focused on the cause of the
claimant’s impairment. 2014 WL 3897749, at *5. But as the
Board explained, it was the doctors who “premised their di-
agnoses regarding a pulmonary impairment on their determi-
nations of the cause of claimant’s hypoxia.” Id. Because the
ALJ permissibly found one doctor more qualified than the
others and credited that doctor’s opinion over the others, the
Board rejected the employer’s argument that the ALJ improp-
erly combined his analysis of the issues of total disability and
disability causation. Id.
    Read that way, Bounds II does not conflict with Street II. In
Street II, the ALJ decided that one doctor’s opinion that the
claimant “did not retain the respiratory capacity to perform
his regular coal mine employment” was suﬃcient to establish
total respiratory disability because the blood gas study results
supported this opinion. 2013 WL 6408512, at *2. The ALJ re-
jected a second doctor’s contrary opinion, which was based
on the conclusion that the claimant’s disabling hypoxemia
was due to nonpulmonary factors, because the ALJ found the
conclusion to be speculative. Id. at *2–3. In aﬃrming the ALJ’s
decision, the Board explained that the medical opinion that
pneumoconiosis did not cause the disabling hypoxemia “does
28                                                  No. 18-2097

not show that claimant does not have a totally disabling res-
piratory impairment pursuant to Section 718.204(b)(2)(iv).”
Id. at *3.
    Consequently, both Bounds II and Street II support the Di-
rector’s argument that the total disability inquiry is distinct
from the disability causation inquiry. In any event, the Board
need not have relied on these cases in adopting the Director’s
argument that the ALJ erred by conflating the two because, as
the Board stated in its opinion, the Director’s argument is con-
sistent with the relevant statutory and regulatory framework,
to which we now turn.
    The Employer asserts that the Act’s unambiguous statu-
tory language and its implementing regulations require the
ALJ to determine if a miner had a respiratory or pulmonary
impairment before invoking the presumption. Focusing on
the use of “respiratory” and “pulmonary” to modify “impair-
ment,” the Employer argues that such language reveals Con-
gress’s intent to limit the invocation of the presumption to
only respiratory and pulmonary impairments. Furthermore,
the Employer asserts that the statutory and regulatory frame-
work presumes that a miner’s respiratory or pulmonary im-
pairment is pneumoconiosis and it limits the rebuttal stand-
ard to establishing that the miner does not have pneumoconi-
osis or that the respiratory or pulmonary impairment did not
arise out of coal mine employment. 30 U.S.C. § 921(c)(4); 20
C.F.R. § 718.305(d)(1).
    Although we agree with the Employer that ALJs must find
that a totally disabling respiratory or pulmonary impairment
exists before the presumption may be invoked, it does not fol-
low that the ALJ may discount evidence that otherwise shows
a totally disabling respiratory or pulmonary impairment (i.e.
No. 18-2097                                                   29

through blood gas results) simply because a physician opines
that the cause of the impairment is cardiac-based. It is clear
from the Act, the regulations, and Board precedent that an
ALJ must decide whether a totally disabling respiratory or
pulmonary disability exists before invoking the presumption,
but that in doing so, the ALJ should not let medical opinion
evidence about the cause of such respiratory or pulmonary
impairment aﬀect the analysis.
    As for the Employer’s argument that the Board blindly
adopted the Director’s factual findings, we hold that the
Board acted within its scope of review and appropriately va-
cated and remanded the ALJ’s decision as not supported by
substantial evidence in the record. By noting that the ALJ mis-
characterized an opinion and improperly discounted an opin-
ion because the ALJ misapprehended the factual record, the
Board is not usurping the ALJ’s factfinding role. Rather, the
Board is fulfilling its own role of ensuring the ALJ’s findings
of fact and conclusions of law are set aside if they are not sup-
ported by substantial evidence or in accordance with law. See
20 C.F.R. § 802.301(a).
    The Employer’s related theory that the Board forced the
ALJ to blindly adopt the Director’s factual findings also does
not prevail. In its opinion, the Board simply instructed the ALJ
on remand to “further consider[]” the evidence. We do not
read the Board’s opinion as coercing the ALJ to reach a certain
result. Rather, the Board pointed out evidence that the ALJ
should acknowledge, but that the ALJ was still free to weigh
as the ALJ saw fit. Furthermore, a significant portion of the
ALJ’s decision on remand involved supplemental medical ev-
idence to which the Board did not have access. Thus, the
Board could not have controlled the ALJ’s findings on remand
30                                                  No. 18-2097

and the ALJ’s ultimate decision on remand could not have
been preordained.
   The Board did not exceed its scope of review by vacating
and remanding the ALJ’s decision.
     C. Finding of Total Disability Established on Remand
   The Employer also argues that the ALJ’s findings on re-
mand as to the total disability inquiry were not supported by
substantial evidence and were contrary to law.
    Starting with Dr. Tazbaz’s opinion, the Employer assigns
error to the ALJ’s finding, “[u]pon further reflection,” that Dr.
Tazbaz’s opinion was well-documented and well-reasoned.
The Employer concedes that “[s]uch finding would be appro-
priate” if the ALJ had not merely copied such findings from
the Board (which had blindly adopted the same findings from
the Director’s brief, according to the Employer). As noted
above, however, we do not view the ALJ as thoughtlessly fol-
lowing the Board’s directive. Based on the ALJ’s decision, it is
clear that the ALJ considered the relevant evidence (including
a wealth of supplemental medical opinion evidence), made
credibility determinations, and weighed diﬀering opinions in
order to reach his independent conclusion.
    The Employer also argues that the ALJ’s crediting of Dr.
Tazbaz’s opinion was not supported by the evidence because
Dr. Tazbaz did not address: (1) how Ross’s chronic obstructive
pulmonary disease and coal workers’ pneumoconiosis would
cause oxygen desaturation with exercise; (2) why the pulmo-
nary function test he performed on Ross produced qualifying
results but the testing Dr. Tuteur performed on Ross four
months later did not; or (3) what evidence or medical research
existed to undermine Drs. Tuteur’s and Selby’s opinions. But,
No. 18-2097                                                    31

the Employer’s first argument is premised on importing the
causation analysis into the disability analysis, in violation of
statutory and regulatory language. Dr. Tazbaz did not need
to explain why chronic obstructive pulmonary disease or coal
workers’ pneumoconiosis would cause Ross’s desaturation
with exercise in order for the ALJ to be able to rely on his opin-
ion as evidence of a totally disabling pulmonary impairment;
the ALJ may rely on Dr. Tazbaz’s conclusion that Ross pro-
duced qualifying blood gas results as evidence of total disa-
bility, even if Dr. Tazbaz believes the cause of the results is
nonpulmonary. See Midland Coal Co., 358 F.3d at 493. As to the
second and third arguments, the record shows that Dr. Tazbaz
discussed the other doctors’ opinions enough to support the
ALJ’s finding that Dr. Tazbaz’s opinion was credible. The stat-
utory and regulatory framework do not require Dr. Tazbaz to
respond to every conflicting data point with a counterpoint or
resolution; that Dr. Tazbaz considered Ross’s full medical rec-
ord before making a medical judgment as to Ross’s diagnoses
was suﬃcient.
    Next, the Employer challenges the ALJ’s finding on re-
mand that Dr. Tuteur deemed Ross to have a totally disabling
pulmonary impairment. According to the Employer, it was
just the opposite: Dr. Tuteur found Ross’s cardiac condition to
be the cause of the disability. And the Employer argues that
the ALJ’s decision should be vacated because ALJs are not al-
lowed to mischaracterize a physician’s opinion or to substi-
tute their own findings for that of a physician’s. Again, the
Employer seeks to use the doctor’s opinion that a cause of an
impairment is nonpulmonary to remove evidence of a totally
disabling pulmonary impairment from the ALJ’s considera-
32                                                 No. 18-2097

tion. To do so is improper under the statute and the regula-
tions; the ALJ reached an appropriate finding as to Dr. Tu-
teur’s opinion of a totally disabling pulmonary impairment.
    Lastly, the Employer disputes the ALJ’s decision to accord
Dr. Selby’s opinion that Ross did not have a pulmonary disa-
bility little weight, emphasizing that Dr. Selby’s opinion was
supported by Dr. Tuteur’s testing in 2012 and by Dr. Selby’s
review of all the materials. Notwithstanding the parts of the
record that support Dr. Selby’s opinion, the ALJ may never-
theless decide that, on balance, Dr. Selby’s opinion was not
well-reasoned because Dr. Selby did not discuss the qualify-
ing blood gas studies or why Ross would be capable of per-
forming his usual coal mine employment.
    In general, the Employer’s theory that something must be
amiss because the ALJ changed his mind on remand is partic-
ularly unpersuasive here because the parties submitted five
additional medical opinions after the Board’s second deci-
sion. Those supplemental medical opinions presented new in-
formation for the ALJ to consider, which ultimately altered
the ALJ’s credibility determinations. For the first time on re-
mand, the doctors were able to consider the complete results
of the 100% blood gas study, which formed the basis of Dr.
Tuteur’s conclusion that a shunt caused Ross’s hypoxemia.
Relevant here, Dr. Tazbaz cast doubt on Dr. Tuteur’s use of
the blood gas study to identify a shunt given that the pre-
ferred way to determine the presence of a shunt is an echocar-
diogram with a bubble study, which Dr. Tuteur did not per-
form. Moreover, Dr. Tazbaz noted that Ross’s treatment rec-
ords relating to his coronary artery bypass graft surgery
showed that his heart and the bypass were functioning
No. 18-2097                                                   33

properly and that his heart disease had been treated surgi-
cally, so it could not be the cause of any major issues for Ross.
In their second supplemental opinions, neither Dr. Tuteur nor
Dr. Selby could refute the utility of a bubble study to confirm
the presence of a shunt, nor did they explain how, in spite of
Ross’s positive cardiac-related medical history, Drs. Tuteur
and Selby nevertheless believed Ross’s impairment was car-
diac-based and not pulmonary-based.
   We hold that the ALJ’s decision to accord more weight to
Drs. Tazbaz’s and Tuteur’s opinions—because he considered
those opinions better-reasoned than Dr. Selby’s and found
them supported by the medical evidence—was rational, sup-
ported by substantial evidence, and in accordance with appli-
cable law. In turn, we conclude that the Board appropriately
aﬃrmed the ALJ’s decision that Ross proved by a preponder-
ance of the evidence that he was totally disabled under
20 C.F.R. § 718.204(b)(2)(iv), that the evidence was suﬃcient
to establish total disability pursuant to 20 C.F.R.
§ 718.204(b)(2), and that Ross invoked the fifteen-year pre-
sumption under 30 U.S.C. § 921(c)(4).
   D. Finding that Presumption Was Not Rebutted on Re-
      mand
    After invoking the fifteen-year presumption on remand,
the ALJ addressed whether the Employer rebutted it. Employ-
ers face an “uphill battle” in attempting to rebut the presump-
tion. R & H Steel Bldgs., Inc. v. Dir., Oﬃce of Workers’ Comp.
Programs, 146 F.3d 514, 518 (7th Cir. 1998). But, the Employer
34                                                  No. 18-2097

advances several theories as to why the ALJ’s decision that it
did not rebut the presumption should be vacated.
    First, the Employer argues that because the ALJ only con-
sidered whether the Employer could rebut legal pneumoco-
niosis, the ALJ failed to review all the medical evidence,
which was contrary to law. This argument misses the mark.
While the ALJ was required to review all medical evidence
before determining if a total disability existed, the Employer
does not cite any authority to support the notion that the ALJ
may not decide that the employer cannot rebut the presump-
tion because the employer cannot rebut one of the requisite
elements. See 20 C.F.R. § 718.305(d)(1)(i).
    Next, the Employer objects that the invocation of the pre-
sumption yields only a presumption of clinical pneumoconi-
osis. But, this argument contravenes the statutory and regula-
tory framework. Section 921(c)(4) specifically provides that
the fifteen-year presumption is triggered when a miner is dis-
abled or has died from “pneumoconiosis,” and both the stat-
utory and the regulatory definitions of pneumoconiosis are
broad: “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); 20 C.F.R.
§ 718.201(a). And as noted above, the regulation further spec-
ifies that this broad definition includes “clinical” and “legal”
pneumoconiosis. 20 C.F.R. § 718.201(a). There is no sugges-
tion that Congress sought to limit the application of the pre-
sumption to only clinical pneumoconiosis. In fact, there is per-
suasive authority from other courts of appeals that have con-
sidered this precise issue and held that the plain language of
§§ 902(b) and 921(c)(4) leads to the conclusion that the pre-
sumption applies to both clinical and legal pneumoconiosis.
No. 18-2097                                                   35

See Consolidation Coal Co. v. Dir., Oﬃce of Workers’ Comp. Pro-
grams, 864 F.3d 1142, 1147 (10th Cir. 2017); Barber v. Dir., Oﬃce
of Workers’ Comp. Programs, 43 F.3d 899, 901 (4th Cir. 1995).
    The Employer argues that research concerning the fifteen-
year presumption showed that the likelihood of a miner de-
veloping clinically significant legal pneumoconiosis was only
14.2% for smoking miners and 7.7% for nonsmoking miners
with “high exposure” to coal mine dust over varying lengths
of time. See Regulations Implementing the Federal Coal Mine
Health and Safety Act of 1969, as Amended, 65 Fed. Reg.
79920-01, 79940-01 (Dec. 20, 2000). And the Employer argues
that this data revealed that even if the “high exposure” miners
worked in the mines for over fifteen years, 85.8% of them
would not develop legal pneumoconiosis, and yet 88% of
them did develop clinical pneumoconiosis. The Employer
thus argues there is insuﬃcient evidence to support a pre-
sumption that a miner with chronic obstructive pulmonary
disease and at least fifteen years of coal mine employment has
legal pneumoconiosis. Given that the law requires a logical
connection between the proven fact and the presumed con-
clusion, the Employer reasons that the fifteen-year presump-
tion does not apply to legal pneumoconiosis. See Mullins Coal
Co. v. Dir., Oﬃce of Workers’ Comp. Programs, 484 U.S. 135, 137,
158–59 (1987) (recognizing the “need for a logical connection
between the proven fact and the presumed conclusion” in ref-
erence to the interim presumption of eligibility for black lung
benefits claims filed between July 1, 1973, and April 1, 1980).
   In response, the Director points to an opinion from the
Tenth Circuit that considered and rejected the same argu-
ment:
36                                                 No. 18-2097

      We fail to see how this study sheds light on Con-
      gress’ intent as to the fifteen-year presumption.
      But in any event, the study is inapposite. It re-
      flects the incidence of respiratory impairment
      among all miners, healthy or unhealthy. The fif-
      teen-year presumption requires a claimant to
      demonstrate that he is totally disabled due to a
      respiratory condition, § 921(c)(4), and thus min-
      ers who successfully invoke the presumption
      have already shown that they fall within the
      class of miners with significant pulmonary dys-
      function.
Consolidation Coal, 864 F.3d at 1148 n.2. We agree with the
Tenth Circuit that the presumption is reasonable for legal
pneumoconiosis. And we do not conclude that the presump-
tion only applies to clinical pneumoconiosis.
    Finally, the Employer argues that the ALJ’s interpretation
of the rebuttal requirements was erroneous and should be va-
cated. The parties devote pages to analyzing, criticizing, and
distinguishing the medical opinion evidence. But, in consid-
ering whether there is support for the Employer’s attempt to
rebut the presumption, the medical opinion evidence may be
simplified as a disagreement between three qualified physi-
cians as to the cause of Ross’s qualifying test results. We may
not reweigh the medical opinion evidence. It was rational for
the ALJ to discredit the opinions of Drs. Tuteur and Selby to
the extent they concluded that Ross did not suﬀer from a pul-
monary impairment because those opinions did not explain
how they eliminated Ross’s thirty years of coal mine dust ex-
posure as a potential cause of his pulmonary impairment, or
how they concluded Ross does not have chronic obstructive
No. 18-2097                                                   37

pulmonary disease given the years of medical treatment rec-
ords documenting the condition and the CT scan reading of
mild to moderate emphysema. Similarly, it was rational for
the ALJ to reject Drs. Tuteur’s and Selby’s opinions that a
shunt was the sole cause of Ross’s disability given that those
doctors did not diagnose pneumoconiosis and they did not
address contrary medical evidence of record, namely Dr. Taz-
baz’s normal cardiac test results and Ross’s extensive cardiac
treatment records that lacked any mention of a shunt.
     Substantial evidence supports the ALJ’s decision to give
little weight to the disability causation opinions of Drs. Tuteur
and Selby. Given that those were the only opinions the Em-
ployer could rely on to support its eﬀort to rebut the presump-
tion, and the ALJ reasonably discredited them, we hold that
the Board appropriately aﬃrmed the ALJ’s finding that the
Employer did not rebut the presumption.
                        III. Conclusion
   For the foregoing reasons, we ENFORCE the Board’s deci-
sion affirming the ALJ’s determination that Ross is entitled to
benefits under the Act.
