ABSTRACT
Industrial activities of all types have used, produced, and disposed of a wide variety of natural, and more recently, synthetic materials. Cancer is the second leading cause of death in the United States. It has been widely publicized that something like one person in four will at some time in life contract cancer from one source or another. Risk ceilings should apply to exposure situations, not merely to individual carcinogens. Once the goal fraction and associated risk ceilings are set, it is possible to envision their application in control and regulation. Risk ceilings corresponding to a selected fraction can be used in specific exposure situations. The use of goal-setting, critical probability and ceiling risk concepts addresses the real problem of risk control for materials such as carcinogens in which information is imperfect and there is a large region between clearly acceptable risks and clearly unacceptable risks.
