Synonyms: Cobalt metal dust; Cobalt metal fume; Cobalt metal powder; Elemental cobalt

OSHA IMIS Code Number: 0720

Chemical Abstracts Service (CAS) Registry Number: 7440-48-4

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: GF8750000

NIOSH Pocket Guide to Chemical Hazards - Cobalt Metal Dust and Fume (as Co): Physical description, chemical properties, potentially hazardous incompatibilities, and more

U.S. Environmental Protection Agency (EPA) Hazard Summary - Cobalt Compounds: Uses, sources and potential exposure, acute and chronic health hazard information, and more

National Toxicology Program (NTP) carcinogenic classification: Not listed

International Agency for Research on Cancer carcinogenic classification: Group 2B [31 MB PDF, 553 pages] (possibly carcinogenic to humans [cobalt and cobalt compounds, evaluated as a group]); Group 2B [4 MB PDF, 353 pages] (possibly carcinogenic to humans [cobalt metal without tungsten carbide])

EPA carcinogenic classification: Not listed

EPA Inhalation Reference Concentration (RfC): Not established

Agency for Toxic Substances and Disease Registry (ATSDR) Inhalation Minimal Risk Level (MRL): 0.0001 mg/m³ (chronic)

NIOSH Immediately Dangerous to Life or Health (ILDH) concentration: 20 mg Co/m³

Notes on Other Potential Health Effects and Hazards

1. Dust may ignite on contact with air or oxygen, and particles may form explosive mixtures in the air (NIOSH/IPCS 2004).
2. One study estimated that an 8-hr TWA exposure to 20 or 50 µg/m3 will result in urinary cobalt levels of about 18 and 32 µg per gram of creatinine, respectively, at the end of the work week (Lison et al. 1994). Another study reported an estimated concentration of about 40 µg/liter of urine for an airborne concentration of 50 µg/m3 (Linnainmaa and Kiilunen 1997).
3. Cobalt does not accumulate in the body and is mainly excreted in urine. Measures of cobalt in blood and urine are indicative of recent exposures (Lauwerys and Lison 1994).
4. Epidemiological data suggest that lung parenchymal reactions resulting from exposure to cobalt-containing dust cannot be induced by pure cobalt metal dust alone but require co-exposure to other compounds (Lison 1996).
5. Several neurological effects may result from cobalt exposure, including memory loss, nerve deafness, and decreased visual acuity (ATSDR 2004).

 Date Last Revised: 9/6/2012

Literature Basis

• ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Cobalt, Elemental and Inorganic Compounds. 2001.
• ATSDR: Toxicological Profile for Cobalt [6 MB PDF, 486 pages]. 2004.
• California Occupational Safety & Health Standards Board: Initial [88 KB PDF, 16 pages] and Final [63 KB PDF, 9 pages] Statement of Reasons February 3, 2001.
• Lauwerys, R. and Lison, D.: Health risks associated with cobalt exposure - an overview. Sci. Total Environ. 150(1-3): 1-6, 1994.
• Linnainmaa, M. and Kiilunen, M.: Urinary cobalt as a measure of exposure in the wet sharpening of hard metal and stellite blades. Int. Arch. Occup. Environ. Health 69(3): 193-200, 1997.
• Lison, D., Bucher, J.-P., Swennen, B., Molders, J. and Lauwerys, R.: Biological monitoring of workers exposed to cobalt metal, salt, oxides, and hard metal dust. Occup. Environ. Med. 51(7): 447-450, 1994.
• Lison, D: Human toxicity of cobalt-containing dust and experimental studies on the mechanism of interstitial lung disease (hard metal disaease). Crit Rev Toxicol. 26 (6): 585-6 16, 1996.
• NIOSH: Occupational Hazard Assessment - Criteria for Controlling Occupational Exposure to Cobalt. 1981.
• NIOSH/IPCS: International Chemical Safety Cards - Cobalt. April 21, 2004.
  

• sampling media: Mixed Cellulose Ester Filter (MCEF) 0.8 microns
  maximum volume: 960 Liters   
  minimum volume: 480 Liters   
  maximum flow rate: 2.0 L/min
  current analytical method: Atomic Absorption Spectroscopy; AAS
  method reference: OSHA Analytical Method (OSHA ID-121)
  method classification: Fully Validated
  alternate analytical method: Inductively Coupled Argon Plasma; ICP-AES/MS
  method reference: OSHA Analytical Method (OSHA ID-125G, OSHA 1006)
  method classification: Fully Validated
  alternate analytical method: Inductively Coupled Argon Plasma; ICP-AES
  method reference: OSHA Analytical Method (OSHA ID-213, for cobalt in cemented tungsten carbide or tungsten alloy matrices)
  method classification: Fully Validated
  note: If the filter is not overloaded, samples may be collected up to an 8-hour period.

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