Maximum Allowable Concentration 3 : The amount of toxic substances, measured in parts per million, which if surpassed could cause tissue damage. See: Threshold Limit Valve
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}