| Agent Name |
Cobalt |
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| CAS Number |
7440-48-4 |
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| Formula |
Co |
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| Major Category |
Metals |
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| Synonyms |
Cobalt metal dust; Cobalt metal fume; [NIOSH] |
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| Category |
Elements, Metallic |
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| Description |
Odorless, silver-gray to black solid; [NIOSH] |
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| Sources/Uses |
Occupational asthma reported in hard metal grinders and diamond polishers; [Malo] Allergic contact dermatitis in electronics workers; [Marks] Cobalt chloride skin allergy often accompanies chromium and nickel sensitization. Affected workers include electroplaters, hairdressers, cement handlers, and metal tool manufacturers and users. [Kanerva, p. 427] Also used in orthopedic prostheses, glass and paint pigments, and catalysts; it may be released in emissions from burning fossil fuels. Cobalt is an essential nutrient in the human diet in the form of Vitamin B12 (cyanocobalamin). Radioactive cobalt is used in medicine and food/equipment irradiation. [ATSDR ToxProfiles] |
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| Comments |
Cobalt is used as a binder along with tungsten and carbon to produce tungsten carbide. Cobalt is the suspected agent of hard metal lung disease. [Harber, p.116] Pulmonary edema can result from heavy exposure to cobalt fumes. [Harber, p. 496] A cross-sectional study of 82 workers in a cobalt refinery with an average exposure of 8 years found mild thyroid dysfunction (decreased T3, T4, and increased TSH). No evidence of pulmonary fibrosis was found in these workers exposed to cobalt alone (not to hard metal). [Reference #1] An epidemic of cardiomyopathy occurred in the 1960s among heavy drinkers of beer containing cobalt. A recent study of cobalt workers correlated cummulative cobalt exposure with echocardiographic changes but not with cardiac dysfunction. [Reference #2] Cobalt is a "hepatotoxic agent." [Zimmerman, p. 4] Can cause immunologic, occupational contact urticaria; [Kanerva 2004, p. 104] See "Cobalt-60" the most important radionuclide. |
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| Reference Link |
Epidemiological survey of workers exposed to cobal...[Br J Ind Med. 1993] - PubMed Result |
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| Exposure Assessment |
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| BEI |
Cobalt in urine = 15 ug/L; cobalt in blood = 1 ug/L; sample at end of shift at end of workweek; |
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| Skin Designation (ACGIH) |
No |
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| Bioaccumulates |
Yes |
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| TLV (ACGIH) |
0.02 mg/m3 |
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| PEL (OSHA) |
0.1 mg/m3, as Co (metal dust and fume) |
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| IDLH (NIOSH) |
20 mg/m3 |
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| Excerpts from Documentation for IDLHs |
It has been reported that animals chronically exposed for 3 years to a cobalt-metal blend at a concentration of 20 mg Co/m3 developed fibrotic lesions in the lungs [Patty 1963]. |
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| Explanatory Notes |
Cobalt with tungsten carbide is classified as 2A (probably carcinogenic to humans). [IARC] |
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| Half Life |
Whole body (depends on compound and route): 5 days to 4 years; [TDR, p. 379] |
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| Reference Link |
Exposure to cobalt in the production of cobalt and...[Occup Environ Med. 2004] - PubMed Result |
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| Adverse Effects |
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| Asthma |
Yes |
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| Toxic Pneumonitis |
Yes |
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| Fibrogenic |
Yes |
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| Skin Sensitizer |
Yes |
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| Hepatotoxin |
Hepatotoxin, Secondary |
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| IARC Carcinogen |
Possible Carcinogen |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: COBALT
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