In coal mining operations where the concentration of respirable dust in the mine atmosphere of any working place contains more than 5 per centum quartz, the Secretary of Health and Human Services shall prescribe an appropriate formula for determining the applicable respirable dust standard under this subchapter for such working place and the Secretary shall apply such formula in carrying out his duties under this subchapter.
(Pub. L. 91–173, title II, §205, Dec. 30, 1969, 83 Stat. 765; Pub. L. 96–88, title V, §509(b), Oct. 17, 1979, 93 Stat. 695.)
"Secretary of Health and Human Services" substituted in text for "Secretary of Health, Education, and Welfare" pursuant to section 509(b) of Pub. L. 96–88 which is classified to section 3508(b) of Title 20, Education.
Section operative six months after Dec. 30, 1969, except to the extent an earlier date is specifically provided for in Pub. L. 91–173, see section 509 of Pub. L. 91–173, set out as a note under section 801 of this title.