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: 14484-64-1; Chemical Formula: [(CH3)2NCS2]3Fe
OSHA formerly applied its generic particulate limit of 15 mg/m3 as an 8-hour TWA (total particulate) to ferbam. The ACGIH has a TLV-TWA of 10 mg/m3 for this odorless black solid. OSHA proposed an 8-hour TWA total particulate PEL of 10 mg/m3 for ferbam, and this limit is established in the final rule. The 5-mg/m3 PEL for the respirable fraction is retained. NIOSH (Ex. 8-47, Table N1) concurs with these limits.
Ferbam, which is a fungicide, has been reported to have an oral LD(50) of more than 17 mg/kg in rats, but rabbits and guinea pigs demonstrated less sensitivity to this substance (Hodge, Maynard, Downs, and Blanchet 1952/Ex. 1-861). Thirty-day dietary studies of rats showed no effect at ferbam doses of 0.01 percent, with fatalities occurring at 0.5 percent. Dogs showed no adverse effects when fed 25 mg/kg of ferbam daily for six months. Inhalation of ferbam affects the upper respiratory tract in humans, in the manner typical of airborne exposures to workplace dusts (Hodge, Maynard, Downs, and Blanchet 1952/Ex. 1-861). NIOSH submitted the only comment on ferbam.
In the final rule, OSHA is reducing the total particulate PEL for ferbam to a 10-mg/m3 8-hour TWA. The Agency concludes that this reduction is necessary to prevent the significant health and safety risks associated with workplace exposures to ferbam. These risks include skin, eye, and upper respiratory tract irritation, which together constitute material health impairments.