No Chronological Preference for Conflicting ABG Studies: Sixth Circuit Reaffirms Deference to ALJ Credibility Findings and Month‑of‑Filing Onset Under the BLBA

Introduction

In Cumberland River Coal Co. v. OWCP (6th Cir. Oct. 14, 2025) (not recommended for publication), the Sixth Circuit denied an operator’s petition for review and affirmed an Administrative Law Judge’s (ALJ) award of federal black lung benefits to former miner Carlos Sturgill. The case centers on two pivotal issues under the Black Lung Benefits Act (BLBA): whether substantial evidence supports an ALJ’s finding of total respiratory disability in the face of conflicting arterial blood gas (ABG) studies and medical opinions, and how to determine the onset date of benefits when the record does not establish a precise month of onset.

The opinion clarifies and underscores two core principles in BLBA adjudication within the Sixth Circuit:

Conflicting ABG studies that appear to show “improvement” do not automatically trigger any “later evidence is better” presumption. Because pneumoconiosis is progressive and irreversible, such conflicts must be assessed for reliability without chronological preference, and ALJs may credit a physician’s reasoned medical explanation for variability.
When the record does not pinpoint the month disability began, and there is no uncontradicted evidence of nondisability after filing, benefits begin in the month of filing.

Parties: Petitioner Cumberland River Coal Company challenged the award made to Respondent miner Carlos Sturgill; the Director, Office of Workers’ Compensation Programs (OWCP), U.S. Department of Labor, appeared as a respondent. Judge Thapar authored the opinion for a panel including Judges Griffin, Thapar, and Mathis.

Summary of the Opinion

The Sixth Circuit applied its “exceedingly narrow” substantial evidence review to the ALJ’s factual findings and deferred to the ALJ’s credibility determinations among three medical experts. The court held:

The ALJ reasonably credited Dr. Mahmood Alam’s opinion that Sturgill was totally disabled, relying on a qualifying ABG study and a reasoned medical explanation that variability across ABG tests can occur in patients with cardiac comorbidities and reduced mobility.
The ALJ reasonably gave less weight to opinions from Drs. Abdul Dahhan and David Rosenberg because they did not reconcile the earlier qualifying ABG study, did not sufficiently analyze the exertional demands of Sturgill’s “usual coal mine work,” and did not adequately explain how acknowledged symptoms (shortness of breath on exertion) squared with an asserted capacity to return to physically demanding mining work.
The “later evidence” preference does not apply where later tests suggest improvement; instead, conflicting studies must be evaluated for reliability without chronological bias, consistent with Sixth Circuit precedent.
The ALJ properly set the onset date as the month of filing (June 2018) because the record lacked a precise onset month and there was no uncontradicted post‑filing evidence of nondisability.

The petition for review was denied.

Analysis

Precedents Cited and Their Influence

Peabody Coal Co. v. Odom, 342 F.3d 486 (6th Cir. 2003) and A & E Coal Co. v. Adams, 694 F.3d 798 (6th Cir. 2012): These cases anchor the deferential standard of review. The court reiterated that it does not reweigh evidence or second‑guess the ALJ’s credibility findings when supported by substantial evidence. This framed the court’s “exceedingly narrow” review posture.
Big Branch Resources, Inc. v. Ogle, 737 F.3d 1063 (6th Cir. 2013): Reinforces that a court will reverse only if no reasonable mind could agree with the ALJ’s findings and that crediting or discrediting medical experts is the ALJ’s prerogative. The panel quoted Ogle to emphasize deference to the ALJ’s weighing of medical opinions.
Morrison v. Tennessee Consolidated Coal Co., 644 F.3d 473 (6th Cir. 2011): Background authority for the 2010 amendments reviving the 15‑year presumption at 30 U.S.C. § 921(c)(4), which presumes disability due to pneumoconiosis for miners with at least 15 years of underground work and total respiratory disability. While the appeal ultimately turned on total disability and credibility, the presumption provides important context: establishing total disability would trigger the presumption’s burden‑shifting in appropriate cases.
Mullins Coal Co. v. Director, OWCP, 484 U.S. 135 (1987): The Supreme Court’s statement that pneumoconiosis is progressive and irreversible. The Sixth Circuit relied on this to reject a simplistic “later is better” approach where later ABG values looked better than earlier ones.
Woodward v. Director, OWCP, 991 F.2d 314 (6th Cir. 1993): The key Sixth Circuit case on handling conflicting test results. Woodward instructs that when later evidence shows apparent improvement, the “later evidence rule” does not apply; instead, the ALJ must evaluate the conflicting tests’ reliability without regard to chronology and reconcile the inconsistency. The court used Woodward to endorse the ALJ’s expectation that defense experts address and reconcile the earlier qualifying ABG study.
Huscoal, Inc. v. Director, OWCP, 48 F.4th 480 (6th Cir. 2022): Confirms an ALJ may probe the internal logic of expert opinions and reject them where reasoning is incomplete or unpersuasive. The panel cited Huscoal to approve the ALJ’s critique of opinions that failed to relate symptoms and test results to the miner’s actual job demands.
Rochester & Pittsburgh Coal Co. v. Krecota, 868 F.2d 600 (3d Cir. 1989): Along with Benefits Review Board decisions Edmiston and Lykins, Krecota supports starting benefits in the month of filing when the record does not establish a precise onset and there is no uncontradicted evidence of nondisability post‑filing. The Sixth Circuit cited these authorities to uphold the ALJ’s onset decision.

Statutory and regulatory provisions framing the decision include:

30 U.S.C. §§ 901–945 (Black Lung Benefits Act); § 902(f) (regulatory authority); § 921(c)(4) (15‑year presumption).
20 C.F.R. § 718.201 (clinical vs. legal pneumoconiosis); § 718.204(b)(1) (definition of total disability by inability to perform usual coal mine work); § 718.204(b)(2)(ii) (ABG studies establishing disability); § 718.204(b)(2)(iv) (physician’s reasoned medical judgment can establish total disability); § 725.202(d) (entitlement framework); § 725.309(c)(4) (subsequent claims require new evidence); § 725.503(b) (onset date rules).

Legal Reasoning

The court’s reasoning tracks the ALJ’s structured evaluation of three medical opinions and the governing regulatory criteria for total disability.

Crediting Dr. Alam’s reasoned opinion and qualifying ABG study. Dr. Alam concluded that Sturgill had pneumoconiosis and a disabling pulmonary impairment. He relied on a qualifying ABG test showing inadequate oxygenation at rest, a metric that independently supports total disability under § 718.204(b)(2)(ii). He also documented functional limitations—Sturgill could not perform exertional tasks due to breathing difficulty—and explained why a later, non‑qualifying ABG did not undermine his disability assessment. Specifically, Dr. Alam cited cardiac disease and reduced mobility as common causes of variability in ABG results. The ALJ deemed that explanation reasoned and persuasive; the Sixth Circuit held that a reasonable mind could agree.
Discounting Dr. Dahhan’s opinion for analytical gaps. Although Dr. Dahhan administered the later, non‑qualifying ABG and opined there was no pulmonary disability, the ALJ identified several flaws:
- He did not describe or quantify the exertional requirements of Sturgill’s “usual coal mine work,” despite acknowledging Sturgill would have difficulty climbing stairs.
- He neither reviewed nor reconciled the earlier qualifying ABG study, contrary to Woodward’s requirement to address conflicting results without chronological preference.
The Sixth Circuit approved the ALJ’s critique, rejecting Cumberland’s argument that “more recent” evidence should automatically control, because later “improvement” is not consistent with a progressive disease and therefore does not get temporal preference.
Discounting Dr. Rosenberg’s opinion for failing to grapple with key evidence and job demands. Dr. Rosenberg concluded Sturgill was not disabled, noting “improved” blood gases and “normal lung function.” But he did not critique the methodology or validity of the earlier qualifying ABG, offered no substantive response to Dr. Alam’s variability explanation, and did not connect Sturgill’s conceded exertional dyspnea to the physical demands of his usual coal work. The ALJ found this insufficient under § 718.204(b)(1)(i), which ties disability to the ability to perform usual coal mine work. The Sixth Circuit held that deference to the ALJ’s credibility ranking was warranted.
Shortness of breath as evidence of disability. The operator argued the ALJ erred by treating breathlessness as dispositive. The court rejected this contention, noting Dr. Alam’s opinion did not rely solely on subjective dyspnea; it was corroborated by objective ABG evidence, consistent with § 718.204(b)(1) and (b)(2).
Reasoned medical judgment can establish total disability even amid mixed test results. The court emphasized § 718.204(b)(2)(iv): an ALJ may find total disability based on a physician’s reasoned medical judgment, even if not every objective test meets qualifying thresholds, so long as the physician explains how the respiratory or pulmonary impairment prevents performance of the miner’s usual work.
Onset date when evidence is indeterminate. Citing § 725.503(b), the court affirmed the ALJ’s choice of the filing month (June 2018) as the onset date because the evidence did not establish a precise onset and there was no uncontradicted post‑filing evidence of nondisability. The presence of contradictory medical opinions—most notably Dr. Alam’s disability assessment—defeated Cumberland’s attempt to delay onset beyond the filing month.

Impact and Practical Implications

Although not precedential, the opinion is instructive for BLBA litigation in the Sixth Circuit and beyond:

Conflicting ABG studies must be reconciled on the merits, not by chronology. When a later ABG is non‑qualifying yet an earlier ABG was qualifying, ALJs need not (and should not) automatically privilege the later result. Parties must provide substantive explanations—methodology, variability due to comorbidities, testing conditions—to establish which study is more reliable.
Medical opinions must address job‑specific exertion. Experts who opine that a miner can return to work must connect the dots: describe the miner’s usual coal mine tasks and credibly explain how the miner’s respiratory capacity allows performance of those tasks despite documented symptoms. Failure to do so justifies reduced weight.
Reasoned medical judgment remains pivotal. Under § 718.204(b)(2)(iv), a well‑explained medical opinion can establish total disability even amid mixed test data. Operators should expect ALJs to credit such opinions where they align with objective indicators and functional limitations tied to job demands.
“Later evidence” arguments are constrained. The decision reiterates that the “later evidence is better” notion applies, if at all, in the direction of progressive worsening—not apparent improvement. Where later data seem “better,” Woodward controls: no chronological preference, and reconciliation is required.
Onset date defaults to filing month absent a precise onset and uncontradicted post‑filing evidence. Parties seeking a later onset must present uncontradicted medical proof of nondisability after filing. Mixed or contested evidence will not suffice to push onset beyond the filing month.
Expert practice pointers. Defense experts should:
- Review all contrary qualifying studies and explicitly reconcile them.
- Quantify and analyze exertional requirements of the miner’s usual coal mine job.
- Address variability explanations (e.g., cardiac comorbidity, testing conditions) with specificity.
- Avoid conclusory “normal lung function” assertions without integrating symptoms and job demands.
Claimant experts should:
- Connect test results and symptoms to concrete job tasks and exertional levels.
- Offer biologically plausible reasons for test variability where present.
- Document objective impairment (e.g., qualifying ABG) and functional limitations in a cohesive narrative.

Complex Concepts Simplified

Clinical vs. Legal Pneumoconiosis (20 C.F.R. § 718.201):
- Clinical pneumoconiosis: Specific dust‑induced diseases recognized by medical diagnosis (e.g., coal workers’ pneumoconiosis).
- Legal pneumoconiosis: Any chronic restrictive or obstructive pulmonary disease significantly related to, or substantially aggravated by, coal dust exposure, including chronic bronchitis or COPD arising from coal mine work.
Total Disability (20 C.F.R. § 718.204(b)(1)): Focuses on whether a miner’s respiratory or pulmonary impairment prevents performance of the miner’s usual coal mine work. It is task‑ and exertion‑specific, not generalized.
ABG Studies and “Qualifying” Results (§ 718.204(b)(2)(ii)): ABG tests measure blood oxygen and carbon dioxide levels. Values at or below regulatory thresholds are “qualifying” and can independently demonstrate total disability. Non‑qualifying values do not necessarily negate disability if a physician’s reasoned judgment explains impairment and functional incapacity.
Physician’s Reasoned Medical Judgment (§ 718.204(b)(2)(iv)): An ALJ may find total disability based on a doctor’s well‑explained opinion connecting medical findings to work incapacity, even if not every objective test is qualifying.
Standard of Review—Substantial Evidence: On appeal, the court asks only whether a reasonable mind could accept the ALJ’s findings. It does not reweigh evidence or reassess credibility; its review is “exceedingly narrow.”
“Later Evidence Rule” in Context: Because pneumoconiosis is progressive, later results showing worsening may carry weight. But when later results look “better,” courts do not prefer them; instead, conflicting tests must be weighed for reliability without chronological bias.
Subsequent Claims (§ 725.309(c)(4)): If a prior claim was denied, a miner must submit new evidence showing a change in a condition of entitlement (e.g., new or worsened impairment) to succeed on a later claim.
Onset Date (§ 725.503(b)): Benefits begin in the month total disability commenced. If the evidence does not establish that month, benefits start in the filing month, unless there is uncontradicted post‑filing proof that the miner was not disabled.
15‑Year Presumption (30 U.S.C. § 921(c)(4)): If a miner has at least 15 years of underground coal mine employment and proves a totally disabling respiratory impairment, the law presumes the disability is due to pneumoconiosis—subject to rebuttal. Establishing total disability is the gateway to this presumption.

Conclusion

Cumberland River Coal Co. v. OWCP reiterates the Sixth Circuit’s deferential appellate stance toward ALJ credibility determinations in BLBA cases and clarifies two practical rules for common evidentiary disputes:

Conflicting ABG studies—especially where later values appear to “improve”—must be evaluated for reliability without chronological preference, and ALJs may credit a physician’s reasoned explanation of variability tied to comorbidities or testing conditions.
When the record does not establish a specific onset month and there is no uncontradicted proof of nondisability after filing, the onset date is the month of filing.

The opinion also underscores that medical opinions must grapple with the real‑world exertional demands of the miner’s usual coal mine work and that a reasoned medical judgment can establish total disability even when objective tests are mixed. For litigants, the case offers a roadmap: experts should review and reconcile all material test results, explain symptoms in relation to job tasks, and avoid conclusory assertions. For adjudicators, it reaffirms the legitimacy of probing expert reasoning and weighing credibility to reach a coherent, evidence‑based determination.