The Role of Risk Assessment in Regulatory Decisions in the United States

Summary

Risk assessment is an art that attempts to produce estimates of the probability of adverse effects for a particular exposure. Thus, a risk assessment may develop a series of probabilities for illness or death which could be associated with varying degrees of exposure to a substance such as an air pollutant, coffee, or the use of an automobile. The regulation of environmental toxicants is a difficult and complex procedure, burdened by scientific uncertainties that permit wide differences in the interpretation of scientific evidence. Two major components of a federal regulatory strategy for carcinogens involve the assessment of health risks from suspected carcinogens, and the regulatory processes that convert such estimates of risk into appropriate regulatory action. There are at least ten Public Laws in the United States that provide for the use of risk assessment. In some cases, risk assessment may be used to set Federal Standards; in others, state- and situation-specific regulations prevail. The probability of adverse health effects in relation to the extent of exposure is considered here, involving the analysis and f combination of epidemiological and other human data with animal effects data. Specific problems considered include the choice of data, combination of data, translation of data from experimental to actual settings, conversion of the results from animal experiments to human response, and the extrapolation of experimental results from high doses to estimated responses at low-ambient concentrations. The various methods used to consider such data in developing a risk assessment are considered. Frequently, there is disagreement about the best method to use for particular circumstances. Thus, there exists a great deal of uncertainty about risk assessments. Some knowledge of the extent of the uncertainty is important in interpreting risk assessment results.