the occupational setting and is not relevant to exposures from zinc borate-treated upholstered furniture. A number of deaths have been reported in humans following inhalation exposure to airborne mixtures containing very high concentrations of zinc. Ten out of 70 people died within 4 d of exposure to a smoke mixture containing approximately 33,000 mg Zn²⁺/kg as zinc chloride, in addition to unknown concentrations of hexachloroethane, calcium silicate, and an igniter (Evans 1945, as cited in ATSDR 1994). Milliken et al. (1963, as cited in ATSDR 1994) and Hjortso et al. (1988) reported fatalities after exposure to high, but unknown concentrations of a smoke mixture generated from zinc chloride smoke bombs. Autopsies revealed diffuse micro vascular obliteration, widespread occlusion of the pulmonary arteries, and extensive interstitial and intra-alveolar fibrosis of the lungs (Hjortsu et al. 1988). Although zinc oxide is associated with metal fume fever, and a large amount of research has been carried out in that area, those results are not a focus of this report because exposure to such fumes created by welding are not relevant to our exposure scenario.

Nausea has been reported following exposure to high concentrations of zinc oxide in humans (Hammond 1944, as cited in ATSDR 1994; Rohrs 1957, as cited in ATSDR 1994). McCord et al. (1926, as cited in ATSDR 1994) reported that several workers from the galvanized industry had decreased red blood cell counts, but Hamdi (1969) reported that workers exposed to zinc compounds had normal red blood cell counts. Routine blood analysis did not reveal liver disease among 12 workers with 4–21 yr of exposure to zinc oxide (Hamdi 1969).

Pulmonary toxicity and reduced survival were reported in female rodents following exposure to zinc oxide/hexachloroethane smoke (119 mg Zn²⁺/m³ for 1 hr/d, 5 d/wk for up to 20 wk) (Marrs et al. 1988). However, the smoke contained a number of other toxic chemicals (e.g., carbon tetrachloride), therefore, the effects can not be attributed to zinc. A single exposure in rats and rabbits to 88–482 mg zinc/m³ as zinc oxide resulted in pulmonary congestion and leukocytic infiltration (Drinker and Drinker 1928; as cited in ATSDR 1994). Amdur et al. (1982) demonstrated a decreased lung compliance following exposure of guinea pigs to 0.73 mg zinc/m³ as zinc oxide for 1 hr. Lam et al. (1982) did not see an effect on ventilation, but did see an effect on functional residual capacity after exposure of guinea pigs to 6.3 mg zinc/m³ as zinc oxide for 3 hr. Deficits in lung function were seen in guinea pigs exposed to zinc oxide dust (3.7–5.6 me zinc/m³) 3 hr/d for up to 6 d (Lam et al. 1985, 1988). No effects were seen at a concentration of 2.2 mg zinc/m³ as zinc oxide (Lam et al. 1988). However, guinea pigs appear to be more sensitive to the pulmonary effects of zinc oxide than humans because of differences in lung structure (Lam et al. 1982).