Section R. 325.2412 - Maximum allowable concentrationsRule 12.
(1) Maximum allowable concentrations of air contaminants based on a repeated 8-hour work day exposure are in tables 1 to 7 in R 325.2413 to R 325.2419.(2) A substance in tables 1 to 6 in R 325.2413 to R 325.2418, which is preceded by A, C, or S, is an especially hazardous contaminant and all of the following precautions shall be taken: (a) If the substance is preceded by "A," then the employer shall not allow a person or any part of his or her anatomy to be exposed to or come in contact with the substance by any respiratory, oral, or skin route.(b) If the substance is preceded by "C," then its MAC means the highest concentration at which an employer may allow a person to be exposed at any time.(c) If the substance is preceded by "S," then an employer shall provide necessary precautions against skin absorption of the contaminant by a person.Mich. Admin. Code R. 325.2412