Aspects of the toxicology of chloroprene: immediate and long-term effects.

The maximum permissible concentration (MPC) of chloroprene was set at 2 mg/m3 in the USSR in the 1940's. The existing MPC is 4 mg/m3. The threshold of systemic effects as a result of chronic chloroprene exposure is l.69 mg/m3. However, the threshold for embryotoxic and mutagenic effects is 0.15 mg/m3. In consideration of this information, setting a new MPC for chloroprene at 0.05 mg/m3 is recommended.