The goal of risk management is to reduce risk. This can be done by either avoiding exposure altogether or instituting engineering and other controls to reduce dose to workers and the public. In practice it is the dose of the agent that is controlled, not the risk itself. Accordingly, the underlying assumption in risk management is that reduction of dose leads to a concomitant reduction in risk. Unfortunately, there is little direct evidence to support this assumption for carcinogen exposures in occupational and environmental settings. 1 In reality, the number of cancers averted for a given diminution in dose cannot be observed directly because risks are very small to begin with. Instead, the number of cancer deaths averted is calculated based on a theoretically determined reduction in risk.