W. Va. Code § 22A-2A-806: Diagnostic testing.

(a) The commission shall require periodic examination and testing of all diesel-powered equipment by a person trained and qualified as required by rules of the commission.

(b) Rules of the commission shall prescribe the scope of the examination and testing and the procedures to be followed, and the rules requiring testing of undiluted exhaust emissions may exceed the written standard operating procedures for such testing and evaluation required by part 75 of the code of federal regulations, set forth in 30 C.F.R. §75.1915(g).