Hepatic injuries of hexachloroethane smoke inhalation: The first analytical epidemiological study

There has been no human epidemiological data regarding the hepatic injuries of hexachloroethane–zinc oxide (HC/ZnO) inhalation. This is the first epidemiological study to investigate whether HC/ZnO inhalation exposure can induce hepatic dysfunction in exposed soldiers. Twenty soldiers, exposed to high concentration of HC/ZnO smoke for 3–10 min in a narrow tunnel (0.6 m in width) during military training, were recruited as exposed group and they were divided into high-exposed group (n = 10) and low-exposed group (n = 10) by the distance from the explosion locale as a surrogate of exposure condition. Another 64 soldiers, not visiting the explosion areas, were recruited as referents. Venous blood was collected for liver function analyses. After log transformation of alanine aminotransferase (ALT) and adjustment for potential confounders, serum ALT in high-exposed soldiers was statistically significantly higher than those of referents for the 3 weeks following exposure. The serum ALT in low exposed soldiers was statistically significantly higher than those of referents at the 3rd week following exposure. The mean ALT levels also showed decreasing gradients by the distance from exposure locale. In addition, the proportions of abnormality on ALT (>40 U/L) were also significantly different among three exposure conditions. Follow-up study showed that the hepatic dysfunction started from 1 to 2 weeks and peaked from 3rd to 5th week after exposure. ALT level was then returned to normal within 6–8 weeks after removing from HC/ZnO smoke exposure. No sequelas in hepatic dysfunction were found until 72 weeks follow-up. Conclusion: We concluded that inhalation of HC/Zn smoke can induce acute, dose-dependent and definite temporal relationship hepatic dysfunction.