30 CFR § 75.151
Tests for methane; qualified person; additional requirement.
Notwithstanding the provisions of §75.150, on and after
January 1, 1971, no person shall be a qualified person for testing for
methane unless he demonstrates to the satisfaction of an authorized
representative of the Secretary that he is qualified to test for methane with
a portable methane detector approved by the Bureau of Mines or the Mine
Safety and Health Administration under Part 22 of
this chapter (Bureau of Mines Schedule 8C).