We investigate the impact of occupational safety and health (OSH) and environmental regulation on the rate of growth of total factor productivity (TFP) in the Quebec manufacturing sector during the 1985-88 period. Our results show that environmental regulation and OSH protective reassignments (a prevention policy with respect to OSH) have led to a reduction in productivity growth, while the presence of mandatory prevention programs and of fines for infractions to OSH rules have led to an increase in productivity growth. Interestingly, this is, to our knowledge, the first result showing that OSH regulation may have had a positive effect on productivity growth.