ABSTRACT
Sulfuric acid (H2SO4) has had an eight-hour time-weighted average (TWA) exposure limit of 1 mg/m3 since 1948, when it was raised from the original (1946) recommendation of 0.5 mg/m3. 1 The Occupational Safety and Health Administration's (OSHA) Permissible Exposure Limit (PEL), 2 the National Institute for Occupational Safety and Health's (NIOSH) recommendation, 2 the West German Maximum Concentration Value (MAK), 3 and the USSR Maximum Allowable Concentration (MAC) 4 are all 1 mg/m3 TWA.
