CHAPTER 5 - Epidemiology of Chemical Warfare Agents

Abstract

This chapter describes the major epidemiological studies of populations who have been exposed to chemical warfare agents. The first full-scale deployment of chemical warfare agents was during World War I in 1915, when the Germans used chlorine gas against French, Canadian, and Algerian troops. Deaths were light, though casualties relatively heavy. A total of 50,965 tons of pulmonary, lachrymatory, and vesicant agents were deployed by both sides of the conflict, including chlorine, phosgene, and mustard gas. Official figures declare about 1,176,500 nonfatal casualties and 85,000 fatalities directly caused by chemical warfare agents during the course of the war. In 1935 Italy used mustard gas during the invasion of Ethiopia in the Second Italo–Abyssinian War with 15,000 chemical casualties reported. Concern regarding potential long-term effects of these exposures continued to be an issue and in 1975 a longitudinal follow-up study of the mortality experience of three samples of World War I veterans was conducted to determine if a single exposure to mustard gas with respiratory injury was associated with increased risk of lung cancer in later life. Rosters of men born between 1889 and 1893 were traced via the Veterans Administration's death records. The 4,136 deaths reported were 95% of that expected. The risk of death from lung cancer among men gassed relative to that for the controls was estimated as 1.3, with 95% confidence limits of 0.9–1.9.