Question # 176

176. A covered facility knows that a mixture it processes contains up to 56 percent of mustard gas, a listed toxic chemical. How should the facility estimate the concentration of mustard gas in this mixture for threshold determinations?
If the facility knows only the upper bound concentration of the listed toxic chemical and has no other information about the concentration of the other components of the mixture, it should use this upper bound (i.e., 56 percent) for threshold determinations.