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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: 0720

CAS number: 7440-48-4

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method:
  • mixed cellulose ester filter (MCEF) 0.8 microns
  • maximum volume: 960 L
  • minimum volume: 480 L
  • maximum flow rate: 2.0 L/min
  • current analytical method: atomic absorption spectroscopy; AAS
  • method reference: OSHA ID-121 (fully validated)
  • alternate analytical method: inductively coupled argon plasma; ICP-AES/MS
  • method reference: OSHA ID-125G and OSHA 1006 (fully validated)
  • alternate analytical method: inductively coupled argon plasma; ICP-AES
  • method reference: OSHA ID-213 (for cobalt in cemented tungsten carbide or tungsten alloy matrices) (fully validated)
  • note: If the filter is not overloaded, samples may be collected up to an 8-hour period.

Exposure Limits and Health Effects (Updated September 6, 2012)

Standard Set By Exposure Limit Health Effect Codes -- Health Effects and Target Organs
OSHA PEL - General Industry
See 29 CFR 1910.1000 Table Z-1
0.1 mg/m3 TWA 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 TWA 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 TWA HE4 -- death at exposures of 1-2 mg/m3
HE10 -- chronic interstitial pneumonitis
HE15 -- allergic dermatitis
NIOSH REL 0.05 mg/m3 TWA HE9 -- pulmonary hypersensitivity
HE10 -- diffuse interstitial fibrosis of the lungs, airway obstruction, bronchitis
HE15 -- allergic dermatitis
ACGIH TLV® 0.02 mg/m3 (cobalt [7440-48-4] and inorganic compounds, as Co (1993)) TWA
HE4 -- myocardial effects
HE9 -- asthma
HE10 -- pulmonary function changes
0.005 mg/m3 (hard metals containing cobalt [7440-48-4] and tungsten carbide [12070-12-1], as Co (2015)) TWA
respiratory sensitizer (RSEN)
CAL/OSHA PELs 0.020 mg/m3 TWA HE4 -- myocardial effects

Carcinogenic classification:

EPA Inhalation Reference Concentration (RfC): Not established

ATSDR Inhalation Minimal Risk Levels (MRLs): 0.0001 mg/m3 (chronic)

NIOSH IDLH 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).

Partial reference list:

  • ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Cobalt, Elemental and Inorganic Compounds. 2016.
  • 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/CEC/IPCS: International Chemical Safety Cards - Cobalt. April 21, 2004.

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