Workplace contaminants. Maximum exposure concentrations

(1) No person shall be exposed to airborne concentrations of chemical or physical agents in excess of the concentrations specified in the Threshold Limit Values and Biological Exposure Indices published by the American Conference of Governmental Industrial Hygienists and as amended periodically. (2) When shifts longer than 8 hours are being worked, the time weighted average (TWA) concentration of airborne contaminants shall be reduced to 50% of the TWA for an eight (8) hour shift. Exposure limits for extended hours of work. (3) The manager shall establish a written program, acceptable to the Inspector, for a qualified person to monitor workplace contaminants to ensure compliance with the established exposure maximums. Monitoring (4) No person shall work or remain in a mine when the oxygen content is less than 18% oxygen unless they are provided with an alternate air supply. oxygen content.