90.203—Certified person; maintenance and calibration.
(b)
To be certified, a person shall pass the MSHA examination on maintenance and calibration procedures for respirable dust sampling equipment.
(c)
A person may be temporarily certified by MSHA to maintain and calibrate approved sampling devices if the person receives instruction from an authorized representative of the Secretary in the maintenance and calibration procedures for respirable dust sampling equipment under this rule. The temporary certification shall be withdrawn if the person does not successfully complete the examination conducted by MSHA on maintenance and calibration procedures within six months from the issue date of the temporary certification.