Zinc-hexachloroethane smoke

Richard RJ, Atkins J, Marrs TC, et al. 1989. The biochemical and pathological changes produced by the intratracheal instillation of certain components of zinc-hexachloroethane smoke. Toxicology 54 79-88. 

A number of studies of the toxicity of zinc oxide/hexachloroethane smoke have been conducted (Brown et al. 1990 Karlsson et al. 1986 Marrs et al. 1983). These studies demonstrate that smoke exposure results in pulmonary inflammation and irritation. When male Porton Wistar rats were exposed to hexachloroethane/zinc oxide smoke for 60 minutes, the lungs showed pulmonary edema, alveolitis, and areas of macrophage infiltration 3 days later. At 14 days, there was interstitial fibrosis and macrophage infiltration. At 28 days, increased fibrosis and macrophage infiltration were noted. However, these same symptoms occurred when the animals inhaled zinc chloride there was no apparent synergism between the zinc chloride and residual hexachloroethane (Brown et al. 1990 Richard et al. 1989). This is consistent with the fact that smoke contains little hexachloroethane and the observation that acute exposure to 260 ppm hexachloroethane had no effects on the lungs of rats (Weeks et al. 1979). 

Brown RF, Marrs TC, Rice P, et al. 1990. The histopathology of rat lung following exposure to zinc oxide/hexachloroethane smoke or instillation with zinc chloride followed by treatment with 70% oxygen. Environ Health Perspect 85 81-87. 

Clode SA, Riley RA, Blowers SD, et al. 1991. Studies on the mutagenicity of a zinc oxide-hexachloroethane smoke. Human Experimental Toxicology 10 49-57. 

Karlsson N, Fangmark I, Haggqvist I, et al. 1991. Mutagenicity testing of condensates of smoke from titanium dioxide/hexachloroethane and zinc/hexachloroethane pyrotechnic mixtures. Mutat Res 260 39-46. 

Marrs TC, Colgrave HF, Edginton JA, et al. 1988. The repeated dose toxicity of a zinc oxide/hexachloroethane smoke. Arch Toxicol 62 123-132. 

Loh, C.-H., Chang, Y.-W., Lion, S.-H., Chang, J.-H., and Chen, H.-L, Case report hexachloroethane smoke inhalation a rare cause of severe hepatic injuries. Environ. Health Perspect., 114, 763-765, 2006. Macaulay, M.B. and Mant, A.K., Smoke-bomb poisoning. A fatal case following the inhalation of zinc chloride... 

In mice, the reported LCTso (product of lethal concentration and time to kill 50% of animals) of zinc chloride is 11,800 mg-min/m (Schenker et al. 1981). However, Schenker et al. (1981) did not provide information on how this value was determined. Following exposure to zinc chloride smoke for 3-20 weeks, mortality was 50% in mice exposed to 121.7 mg zinc/m (compared to 20% in controls) and 22% in guinea pigs exposed to 119.3 mg zinc/m (compared to 8% in controls) (Marrs et al. 1988). The smoke was similar to that described by Evans (1945) and also contained zinc oxide, hexachloroethane, and other compounds. 

Zinc hexachloroethane (HC) mixtures have been successfully appHed since World War 1 as a source of hygroscopic ZnCl2-based aerosol in the so-called HC smokes [5]. However, on hydrolysis, ZnCl2 yields highly corrosive solutions that destroy material and cause severe lesions to living tissue and are held responsible for a numerous deaths among soldiers on inhalation of HC-based smokes [6]. 

Smoke-Generating Devices. Smoke generators are used by the military for daytime obscuration and signaling. For field use where portable stable systems ate requited, pyrotechnic devices are often employed. The primary composition since the 1940s has been HC smoke, which generates a cloud of zinc chloride, ZnCl, smoke by a series of reactions between hexachloroethane, C2Clg(HC), zinc oxide, and aluminum (3) (eq. 4—6). The zinc regenerated in... 

Another type of smoke mixture, a volatile hygroscopic chloride for thermal generation, has the U.S. Army designation HC, type C. It is composed of ca 6.7 wt % grained aluminum, 46.7 wt % zinc oxide ZnO, and 46.7 wt % hexachloroethane [67-72-17, The ratio of zinc oxide to... 

White smoke compositions based on hexachloroethane with zinc, zinc oxide and <5% aluminium or <10% calcium silicon... 

Releases may also occur from the use of this chemical in smoke and pyrotechnic devices. Hexachloroethane content of the smoke devices is about 44.5-46% of the total solid material. The smoke device bums, producing smoke which is mainly zinc chloride, but contains some hexachloroethane. It was estimated that about 0.3-5% of the mass of the reagents in the device is released to air as hexachloroethane in the smoke, assuming a 70% bum efficiency (Katz et al. 1980 Novak et al. 1987). On this basis, it was estimated that during 1982-1984, a maximum of about 6,683 kg (14,700 pounds) of hexachloroethane was released to the atmosphere at Fort Irwin, California, a major military training facility (Novak et al. 1987). Hexachloroethane in smoke (aerosol) was measured in a wind tunnel at concentrations ranging from 0.64-1.26 mg/m3 (average 0.89 mg/m3) (Cataldo et al. 1989). 

Marrs TC, Clifford WE, Colgrave HF. 1983. Pathological changes produced by exposure of rabbits and rats to smokes from mixtures of hexachloroethane and zinc oxide. Toxicol Lett 19 247-252. 

The original HC smoke mixtures (Type A) contained zinc metal and hexachloroethane, but this composition is extremely moisture- sensitive and can ignite spontaneously if moistened. An alternative approach involves adding a small amount of aluminum metal to the composition, and zinc oxide (ZnO) is used in place of the moisture-sensitive metal. Upon ignition, a sequence of reactions ensues of the type [6]... 

For use in trench warfare, for the purpose of obscuring the situation from the sight of the enemy, a very satisfactory dense white or gray smoke is procured by burning a mixture of zinc dust and hexachloroethane. The mixture requires a strong starting fire. The smoke consists largely of finely divided zinc chlo-... 

This is used for white smoke composition in combination with zinc dust and hexachloroethane, It seems that the higher the purity is, the whiter the smoke colour is. The smoke composition is generally packed in a tin case, and the apparent specific volume is important in manufacture if it is too small the can is not filled and if it is too large, the case cannot be filled with the amount defined in the specification. The apparent specific gravity of this material on the market lies between about 0.5 hg and 1.0 kg per litre. 

A safe composition like white smoke, which consists of hexachloro-ethane, zinc dust and zinc oxide, cari be mixed with a mixer like the one used for concrete. In this case, the light zinc oxide is placed first into the mixer, then hexachloroethane and lastly the heavy zinc dust. 

Anderson, D., Blowers, S.D., Marrs, T.C., and Rice, P., An in vitro and an in vivo unscheduled DNA synthesis assay with zinc oxide-hexachloroethane (Zn/HCE) smoke. Hum. Exp. Toxicol., 15, 38-44, 1996. 

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