SULPROFOS

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: 35400-43-2; Chemical Formula: C₁₂H₁₉O₂PS₃

OSHA’s Z tables formerly had no limit for sulprofos. The ACGIH has an exposure limit of 1 mg/m³ as an 8-hour TWA. The proposed PEL was 1 mg/m³ as an 8-hour TWA; NIOSH (Ex. 8-47, Table N1) concurred with this limit, and OSHA establishes this limit in the final rule. Sulprofos, also known as the insecticide BolstarR, is a tan liquid.

Kimmerle (1982b, as cited in ACGIH 1986/Ex. 1-3, p. 547) conducted an extensive animal study on the effects of sulprofos. He reported that the acute toxicity of sulprofos is species-dependent; rats have an oral LD(50) of 100 to 300 mg/kg and mice have an oral LD(50) of 1600 to 1800 mg/kg. The reported dermal LD(50)s are greater than 1000 ml/kg in rats and 800 to 1000 mg/kg in rabbits. In rabbits, sulprofos did not irritate the skin or eyes, and it had no dermal-sensitization effects in guinea pigs. Inhalation studies showed no fatalities in rats exposed to aerosol concentrations of up to 4130 mg/m³ of sulprofos over a period of four hours. In a three-week inhalation study in which rats were exposed to aerosol concentrations of 6, 14, or 74 mg/m³, the two highest concentrations produced cholinergic symptoms; no observable effects were seen at the lowest concentration. Two-year feeding studies by Kimmerle (1982b, as cited in ACGIH 1986/Ex. 1-3, p. 547) in dogs, rats, and mice showed that sulprofos concentrations of 150 ppm, 250 ppm, or 400 ppm were tolerated by all species, with no sulprofos-related tissue changes, signs of toxicity, or oncogenic effects. The overall NOELs were 10 ppm in dogs, 6 ppm in rats, and 2.5 ppm in mice. Kimmerle’s ingestion studies in rats and rabbits dosed at levels of 3, 10, or 30 mg/kg/day of sulprofos showed no embryotoxic or teratogenic effects in these animals, and a three-generation diet study in rats also produced no adverse reproductive effects. Mutagenic studies reported by the same author in mice were negative. Separate subacute inhalation studies also showed no effects on blood cholinesterase levels in rats exposed to 6 mg/m³ (Zielhuis and van der Kreek 1979/Ex. 1-613). There are no reported cases of poisoning in humans (ACGIH 1986/Ex. 1-3, p. 547). NIOSH was the only commenter on sulprofos.

In the final rule, OSHA is establishing an 8-hour TWA limit of 1 mg/m³ for sulprofos. This agency concludes that this limit will protect workers from the significant risk of cholinesterase inhibition, the most sensitive indicator of exposure to this previously unregulated substance. The Agency has determined that this limit will substantially reduce this significant risk, and that cholinesterase inhibition constitutes a material impairment of health.