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Cobalt, Metal, Dust & Fume (as Co)

General Description

  • 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

Exposure Limits and Health Effects

Exposure Limit Limit Values HE Codes Health Factors and Target Organs
OSHA Permissible Exposure Limit (PEL) - General Industry
See 29 CFR 1910.1000 Table Z-1
0.1 mg/m3
HE4 Death at exposures of 1-2 mg/m3
HE10 Chronic interstitial pneumonitis
HE15 Allergic dermatitis
OSHA PEL - Construction Industry
See 29 CFR 1926.55 Appendix A
0.1 mg/m3
HE4 Death at exposures of 1-2 mg/m3
HE10 Chronic interstitial pneumonitis
HE15 Allergic dermatitis
OSHA PEL - Shipyard Employment
See 29 CFR 1915.1000 Table Z-Shipyards
0.1 mg/m3
HE4 Death at exposures of 1-2 mg/m3
HE10 Chronic interstitial pneumonitis
HE15 Allergic dermatitis
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) 0.05 mg/m3
HE9 Pulmonary hypersensitivity
HE10 Diffuse interstitial fibrosis of the lungs, airway obstruction, bronchitis
HE15 Allergic dermatitis
American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) (1993)

Cobalt [7440-48-4] and inorganic compounds, as Co (1993)

Hard metals containing Cobalt [7440-48-4] and Tungsten carbide [12070-12-1], as Co (2015)
0.02 mg/m3

0.005 mg/m3 TWA; RSEN; A2; BEI
HE4 Myocardial effects
HE9 Asthma
HE10 Pulmonary function changes
CAL/OSHA PEL 0.020 mg/m3 TWA HE4 Myocardial effects

  • National Toxicology Program (NTP) carcinogenic classification: Not listed
  • International Agency for Research on Cancer carcinogenic classification: Group 2B (possibly carcinogenic to humans [cobalt and cobalt compounds, evaluated as a group]); Group 2B (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. 2004.
    • California Occupational Safety & Health Standards Board: Initial and Final 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.

Monitoring Methods used by OSHA

Laboratory Sampling/Analytical Method:
  • 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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