1-CHLORO-1-NITROPROPANE

OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.

CAS: 600-25-9; Chemical Formula: CH₃CH₂CHClNO₂

OSHA’s former time-weighted average limit for 1-chloro-1-nitropropane was 20 ppm. The ACGIH has a TLV-TWA of 2 ppm for this flammable liquid (ACGIH 1986/Ex. 1-3). The proposed PEL was 2 ppm as an 8-hour TWA, and NIOSH (Ex. 8-47, Table N1) concurs with this limit. The final rule promulgates a 2-ppm 8-hour TWA PEL for 1-chloro-1-nitropropane.

1-Chloro-1-nitropropane is the most acutely toxic of the fungicides known as the chloronitropropanes. In an inhalation experiment, two rabbits were exposed for six hours to a concentration of 393 ppm, after which one rabbit died; at an average concentration of 2574 ppm, both rabbits died. Guinea pigs tested under the same conditions survived these exposures. The oral LD(50) for rabbits determined in the same study was between 50 and 100 mg/kg (Machle, Scott, Treon et al. 1945/Ex. 1-349). Other members of this family of fungicides show lesser skin and lung irritation but do have higher ingestion toxicities (Patty 1963i, as cited in ACGIH 1986/Ex. 1-3, p. 132). Exposure to high concentrations of 1-chloro-1-nitropropane can cause heart muscle, liver, and kidney damage (Patty 1963i, as cited in ACGIH 1986/Ex. 1-3, p. 132). OSHA received no comments on this substance, except for those from NIOSH. The ACGIH considers chloronitropropane to be more toxic than nitropropane, for which a TLV-TWA of 25 ppm has been established.

In the final rule, OSHA is establishing an 8-hour TWA PEL of 2 ppm. The Agency concludes that this limit will protect exposed employees from the significant risk of skin and upper respiratory tract irritation and of systemic toxicity, which constitute material health impairments that are potentially associated with 1-chloro-1-nitropropane exposure at the former PEL.