estimates of permissible exposure levels (CDC, 1988), the exposures actually reaching the breathing zone of chamber subjects (from the above example, 0.1 mg/m³ sulfur mustard breakthrough with a gas mask rated at 1,000 PF) may have been more than 1,000 times the general population agent control limits (0.0001 mg/m³ for sulfur mustard), and 33 times the control limits for occupational exposure (0.003 mg/m³ for sulfur mustard). In reality, some of the subjects in the chamber tests and field trials almost certainly breathed concentrations 10 or more times the 0.1 mg/m³ level for at least a part of their exposures.

The focus here on chamber and field test subjects is not meant to discount the probable exposure levels experienced by those who were involved in the production or handling of mustard agents and Lewisite. Indeed, as outlined above, the poor safety record of the Chemical Warfare Service during the peak years of production, the high rate of agent-induced injuries, and the anecdotal reports of perceptible odors of sulfur mustard in the manufacturing areas argue that workers and gas handlers were often exposed to levels of mustard agents and Lewisite sufficient to cause short- and long-term health effects. Thus, these individuals should also be considered at risk for any of the adverse health effects this report identifies.

In conclusion, the dose of sulfur mustard to the skin, eye, and respiratory tracts of the human subjects was substantial, especially in the case of the subjects involved in the chamber tests. Doses to the skin were probably equivalent to those received under combat conditions. Consideration of the probable gas mask leakage, additional exposures from contact or vapors from the clothing, accidents, and the documented signs and symptoms in the chamber test records indicate that the doses received by the human subjects were equivalent to those received in occupational exposures and, perhaps, even battlefield exposures.