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: 10210-68-1; Chemical Formula: Co2(CO)8
OSHA had no former limit for cobalt carbonyl. The ACGIH has a TLV-TWA of 0.1 mg/m3 (measured as cobalt) for this substance, which is a solid that decomposes at 50 °C. The proposed PEL was 0.1 mg/m3 as an 8-hour TWA, and NIOSH (Ex. 8-47, Table N1) concurs with this limit, which is established by the final rule.
Sax (Dangerous Properties of Industrial Materials, 6th ed., 1984) reports that cobalt carbonyl has a moderate-to-high order of toxicity by the oral route. The oral LD(50) in mice is 377.7 mg/kg; in rats, it is 753.8 mg/kg (Spiridonova and Shabalina 1973/Ex. 1-1098). The hazards of exposure to the metal carbonyls range from relatively low (for iron pentacarbonyl) to extremely serious (for nickel carbonyl) (Stokinger 1981e, in Patty’s Industrial Hygiene and Toxicology, 3rd rev. ed., Vol 2A, pp. 1797-1806); the greater the toxicity of the metal and the more stable and volatile the carbonyl, the more hazardous the compound. Exposure to any of the metal carbonyls causes the same symptoms of nausea, dizziness, headache, substernal pain, coughing and dyspnea (Stokinger 1981e). Evidence concerning any chronic effects of long-term exposure is lacking (ACGIH 1986/Ex. 1-3, p. 145). Only NIOSH commented on this substance.
In the final rule, OSHA establishes an 8-hour TWA PEL of 0.1 mg/m3 TWA for cobalt carbonyl to protect against the significant risk of headache, nausea, and pulmonary effects, which are material impairments of health that are associated with occupational exposure to this substance at levels above the new PEL. The Agency concludes that this limit will substantially reduce these significant risks.