The clinical and epidemiologic literature on health effects of sulfur mustard covers three types of exposure situations: (1) chronic occupational exposures incurred in the manufacture of the mustard agent; (2) acute combat exposures; and (3) medical use as antitumor drugs.
There is some relatively recent epidemiologic literature on occupational exposure to mustard agents in British and Japanese munitions factories. Several studies suggest that workers who were chronically exposed to mustard agents developed chronic nonmalignant respiratory effects (Easton et al., 1988; Manning et al., 1981; Nishimoto et al., 1970). In the British population, chronic respiratory disease has been reported to occur even among workers with only a few years of employment (Easton et al., 1988).
In a cohort mortality study of 511 employees at a manufacturing plant in England, a significant excess of deaths due to pneumonia was found (Manning et al., 1981). In a more extensive examination of this same plant, Easton examined the mortality patterns of an enlarged cohort of 3,500 workers and reported standardized mortality ratios (SMRs, measures of relative risk) for specific causes of death (Easton et al., 1988). Findings included statistically significant excesses of nonmalignant respiratory disease (SMR = 143), including subcategories of influenza and pneumonia (SMR = 143), bronchitis (SMR = 159), and asthma (SMR = 151). These excesses were present even among those with less than three years of employment at the plant, and were not related to duration of employment. The finding of excess mortality due to nonmalignant respiratory disease observed shortly after initial exposure is consistent with the follow-up studies of combat survivors, in which bronchitis and emphysema were found to be present within months of the acute exposure (see below).
Workers exposed to sulfur mustard and Lewisite in a Japanese production plant were surveyed for respiratory morbidity 25 years after production had ceased (Nishimoto et al., 1970). The survey included chronic symptoms and pulmonary function assessments, that is, forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). The study group of 1,403 represented 62 percent of those identified from among the 5,000 total former employees of the plant. Based on an internal comparison, more highly exposed workers reported more chronic bronchitis and had slightly lower FEV1/FVC than either a less-exposed or unexposed clerical group of coworkers. Compared to groups of unexposed patients at a Chicago respiratory clinic and