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: 1563-66-2; Chemical Formula: C12H15NO3
H.S. No. 1068
Previously, OSHA had no limit for carbofuran. The ACGIH has a TLV-TWA of 0.1 mg/m3 for this white crystalline solid. The proposed PEL for carbofuran was 0.1 mg/m3 as an 8-hour TWA, and NIOSH concurred with this limit (Ex. 8-47, Table N1), which is established in the final rule.
Tobin (1970/Ex. 1-935) reports that the LC(50) of 50-percent wettable carbofuran powder is 108 mg/m3 for male and 133 mg/m3 for female rats; a respiratory LC(50) of 53 mg/m3 for guinea pigs exposed to the 75-percent wettable powder is also reported (Tobin 1970/Ex. 1-935). Rhesus monkeys did not display cholinesterase depression at levels equivalent to 0.56 mg/m3 of 75-percent wettable powder (Tobin 1970/Ex. 1-935). Chronic feeding studies in the rat have shown no effects at 25 ppm; in the dog, the no-effect level was 20 ppm (Gaines, unpublished data, as cited in ACGIH 1986/Ex. 1-3, p. 100). Inhibition of plasma, erythrocyte, and brain cholinesterase levels was evident at levels of 50 ppm in the diet (Tobin 1970/Ex. 1-935). Six-hour exposures at levels of 0.86 mg/m3 caused significant cholinesterase inhibition in animals (Tobin 1970/Ex. 1-935).
Workers exposed at concentrations approaching 0.1 mg/m3 have not shown any adverse effects (Tobin, personal communication to ACGIH TLV Committee, as cited in ACGIH 1986/Ex. 1-3, p. 100). No comments, other than NIOSH's, were received on carbofuran.
In the final rule, OSHA is establishing a permissible exposure limit of 0.1 mg/m3 as an 8-hour TWA for this substance to protect employees from the significant risk of cholinesterase inhibition potentially associated with exposure to this previously unregulated substance. The Agency concludes that this limit will substantially reduce this significant occupational risk of material impairment of health.
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