Zinc oxide fume, occupational exposure

The most significant occupational exposures to zinc would occur during the smelting and refining of zinc ore. The standards for occupational exposure have been estabUshed at a level to prevent the onset of metal fume fever. This temporary condition is caused by excessive exposure to freshly formed fumes of zinc oxide and results in flulike symptoms of fever, chills, headache, muscle pain, nausea and vomiting. 

National Institute for Occupational Safety and Health recommended exposure limits 5mgm for total zinc oxide dust as a TWA for up to a 10 h workday and a 40h workweek and a 15 min ceiling of 15mgm (based on the risk of metal fume fever). 

Epidemiological and Human Dosimettv Studies. Acute high-level exposure to zinc by inhalation resulted in respiratory irritation and metal fume fever (Blanc et al. 1991 Hjortso et al. 1988 Johnson and Stonehill 1961 Linn et al. 1981 Schenker et al. 1981 Sturgis et al. 1927). Welders are a subpopulation of workers who have a high potential for exposure to zinc oxide. Most of the available studies did not report exposure levels or used a small number of subjects. Studies that correlate occupational exposure to zinc with health effects would be useful. A number of human oral exposure studies have shown that excess levels of zinc can result in anemia, pancreatic damage, decreased serum HDL cholesterol levels, and immunotoxicity (Black et al. 1988 Chandra 1984 Hooper et al. 1980). There are insufficient data for establishing dose-response relationships. 

Up to 30% of ingested zinc is absorbed from the small intestine, although absorption is controlled by a homeostatic mechanism. Despite its essentiality, too much zinc interferes with iron and copper metabolism which may result in copper deficiency. Excessive absorption can result in symptoms such as nausea, cramps and vomiting. Inhalation of zinc, zinc oxide and zinc chloride fumes by occupationally exposed workers causes pulmonary oedema and metal fume fever, with symptoms such as fever, chills, sweating and weakness occurring within 4-6 hours of exposure. Chronic inhalation of zinc compounds can result in liver damage. 

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