Tungsten carbide (cemented)

Agent Name
Tungsten carbide (cemented)
Alternative Name
Hard metals containing Cobalt and Tungsten carbide
CAS Number
11107-01-0; 12718-69-3; 12070-12-1;
Major Category
Cemented tungsten carbide; Cemented WC; Hard metal; [NIOSH] Hard metals containing Cobalt [7440-48-4] and Tungsten carbide [12070-12-1], as Co; [ACGIH]
Metals, Inorganic Compounds
A mixture of tungsten carbide, cobalt, and sometimes other metals & metal oxides or carbides; [NIOSH]
Used to manufacture hard metal tools; [LaDou, p. 377] Occupational asthma reported in a metal grinder; [Malo] Used in construction, metalworking, mining, and oil/gas drilling industries; Workers exposed during tool grinding and saw blade sharpening/retipping; Exposure may occur during detonation gun welding; [ACGIH]
The tungsten carbide (WC) content is generally 85-95% and the cobalt content is generally 5-15%. [NIOSH] Hard metal lung disease is caused by the composite material, a mixture of cobalt and tungsten carbide; It is thought that inhaled cemented tungsten carbide injures the lung by releasing toxic oxygen species; Also may occur after exposure to cobalt metal powder mixed with iron and diamond dust in diamond polishers; There is no evidence that cobalt metal alone or other cobalt compounds can cause hard metal disease; [Nordberg, p. 753] "Sprince and colleagues (1984) reported that interstitial and obstructive lung disease was found in 11 of 290 subjects who worked at two tungsten carbide production plants.' [ACGIH] Skin sensitization to cobalt can occur in the hard metal industries. [Marks, p. 79] See "Tungsten." See "Cobalt." This TLV is listed by ACGIH under "Hard metals containing Cobalt and Tungsten carbide."
Biomedical References

Exposure Assessment

Cobalt in urine = nonquantitative; sample at end of shift at end of workweek;
0.005 mg/m3, as Co, thoracic particulate matter
Explanatory Notes
NIOSH REL = 0.05 mg/m3 (containing >2% Co) & 0.015 mg/m3 (containing >0.3% Ni); "This TLV does not apply to either tungsten carbide or cobalt exposures alone in the absence of the other material." [ACGIH] See TLVs for "Tungsten and compounds."

Adverse Effects

Skin Sensitizer
IARC Carcinogen
Probable (2a)
NTP Carcinogen
Anticipated human carcinogen
ACGIH Carcinogen
Suspected Human

Diseases, Processes, and Activities Linked to This Agent


Occupational diseases associated with exposure to this agent:


Industrial Processes with risk of exposure: