20 C.F.R. § 718.202 : Employees' Benefits — OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR — FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, AS AMENDED — STANDARDS FOR DETERMINING COAL MINERS' TOTAL DISABILITY OR DEATH DUE TO PNEUMOCONIOSIS — DETERMINING ENTITLEMENT TO BENEFITS — Determining the existence of pneumoconiosis

(a) A finding of the existence of pneumoconiosis may be made as follows in paragraphs (a)(1) through (4) of this section:
(1) A chest X-ray conducted and classified in accordance with §718.102 may form the basis for a finding of the existence of pneumoconiosis. Except as otherwise provided in this section, where two or more X-ray reports are in conflict, in evaluating such X-ray reports consideration must be given to the radiological qualifications of the physicians interpreting such X-rays (see §718.102(d)).
(2) A biopsy or autopsy conducted and reported in compliance with §718.106 may be the basis for a finding of the existence of pneumoconiosis. A finding in an autopsy or biopsy of anthracotic pigmentation, however, must not be considered sufficient, by itself, to establish the existence of pneumoconiosis. A report of autopsy must be accepted unless there is evidence that the report is not accurate or that the claim has been fraudulently represented.
(3) If the presumptions described in §718.304 or §718.305 are applicable, it must be presumed that the miner is or was suffering from pneumoconiosis.
(4) A determination of the existence of pneumoconiosis may also be made if a physician, exercising sound medical judgment, notwithstanding a negative X-ray, finds that the miner suffers or suffered from pneumoconiosis as defined in §718.201. Any such finding must be based on objective medical evidence such as blood-gas studies, electrocardiograms, pulmonary function studies, physical performance tests, physical examination, and medical and work histories. Such a finding must be supported by a reasoned medical opinion.
(b) A claim for benefits must not be denied solely on the basis of a negative chest X-ray.
(c) A determination of the existence of pneumoconiosis must not be made-
(1) Solely on the basis of a living miner's statements or testimony; or
(2) In a claim involving a deceased miner, solely on the basis of the affidavit(s) (or equivalent testimony) of the claimant and/or his or her dependents who would be eligible for augmentation of the claimant's benefits if the claim were approved.

20 C.F.R. § 718.202

79 FR 21612, 4/17/2014