total disability

(A) in the case of a living miner, such regulations shall provide that a miner shall be considered totally disabled when pneumoconiosis prevents him or her from engaging in gainful employment requiring the skills and abilities comparable to those of any employment in a mine or mines in which he or she previously engaged with some regularity and over a substantial period of time;

(B) such regulations shall provide that (i) a deceased miner's employment in a mine at the time of death shall not be used as conclusive evidence that the miner was not totally disabled; and (ii) in the case of a living miner, if there are changed circumstances of employment indicative of reduced ability to perform his or her usual coal mine work, such miner's employment in a mine shall not be used as conclusive evidence that the miner is not totally disabled;

(C) such regulations shall not provide more restrictive criteria than those applicable under section 423(d) of title 42; and

(D) the Secretary of Labor, in consultation with the Director of the National Institute for Occupational Safety and Health, shall establish criteria for all appropriate medical tests under this subsection which accurately reflect total disability in coal miners as defined in subparagraph (A).

(2) Criteria applied by the Secretary of Labor in the case of—

(A) any claim arising under part B of this subchapter or subject to a determination by the Secretary of Labor under section 945(a) 1 of this title;

(B) any claim which is subject to review by the Secretary of Labor under section 945(b) 1 of this title; and

(C) any claim filed on or before the effective date of regulations promulgated under this subsection by the Secretary of Labor;

shall not be more restrictive than the criteria applicable to a claim filed on June 30, 1973, whether or not the final disposition of any such claim occurs after the date of such promulgation of regulations by the Secretary of Labor.