Workplace exposures to cobalt, usually in combination with other materials, can cause asthma or pulmonary fibrosis, or in rare instances, both diseases. Workers at risk include (1) those engaged in the manufacture of 'hard metal,' a mix of powdered tungsten carbide to which 6% to 15% cobalt is added and then heated to high temperatures. Hard metal has a very high temperature resistance and a hardness approximating that of diamonds; (2) workers who machine hard metal objects; (3) gem polishers in the diamond industry who use cobalt-faced polishing disks; and (4) those who use cobalt- containing materials in high-temperature metallurgy. Asthma, although uncommon, is more frequent than pulmonary fibrosis and resembles occupational asthma from other exposures. No clear-cut immunologic mechanisms have been identified. The pulmonary fibrosis is unique in that some cases are associated with a characteristic multinucleated giant cell in the alveolar spaces. This same cell can be found in the bronchoalveolar lavage fluid. When present in a patient with a known exposure, no additional diagnostic procedures are needed. Other cases of lung fibrosis secondary to exposure to cobalt-containing materials lack this distinctive cell and are indistinguishable from the usual nonspecific form of lung fibrosis. There is nonspecific therapy for these diseases. Early recognition of the cause, prompt removal from additional exposure no matter how small, and the usual therapy for either the airway or the parenchymal disease should be instituted promptly.
- Hard metal
- Occupational lung disease
- Pulmonary fibrosis
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine