30 CFR § 77.102
Tests for methane; oxygen deficiency; qualified person, additional requirement.
Notwithstanding the provisions of §77.101
, on and after
December 30, 1971, no person shall be a qualified person for testing for
methane and oxygen deficiency unless he has demonstrated to the satisfaction
of an authorized representative of the Secretary that he is able and
competent to make such tests and the Mine Safety and Health Administration
has issued him a current card which qualifies him to make such tests.