The legal framework underlying chemical regulation influences both the  extent to which risk assessment is needed for regulatory decision making  and how risk assessments are supposed to be conducted. Comparison of risk  assessment estimates from different agencies and programs therefore  requires careful consideration of these contextual differences. Objectives, Scope, and Methodology

	Scope and Objectives

As requested, our review focused on the chemical risk assessment  procedures, assumptions, and policies of four federal agencies with  responsibilities for regulating or managing risks from potential exposure to  chemicals—the Environmental Protection Agency (EPA), the Food and  Drug Administration (FDA) within the Department of Health and Human  Services (HHS), the Occupational Safety and Health Administration  (OSHA) within the Department of Labor, and the Department of  Transportation’s (DOT) Research and Special Programs Administration  (RSPA—in particular the Office of Hazardous Materials Safety). Our  specific objectives were to identify and describe (1) the general context for  the agencies’ chemical risk assessment activities; (2) what the agencies  view as their primary procedures for conducting risk assessments; (3) what  the agencies view as the major assumptions or methodological choices in  their risk assessment procedures; and (4) the agencies’ procedures or  policies for characterizing the results of risk assessments. That objective is, however, addressed in the letter portion of  this report.)
What GAO Found

As used in public health and environmental regulations, risk assessment is the systematic, scientific description of potential harmful effects of exposures to hazardous substances or situations. It is a complex but valuable set of tools for federal regulatory agencies to identify issues of potential concern, select regulatory options, and estimate the range of a forthcoming regulation's benefits. However, given the significant yet controversial nature of risk assessments, it is important that policymakers understand how they are conducted, the extent to which risk estimates produced by different agencies and programs are comparable, and the reasons for differences in agencies' risk assessment approaches and results. GAO studied the human health and safety risk assessment procedures of the Environmental Protection Agency, the Food and Drug Administration, the Occupational Safety and Health Administration, and the Department of Transportation's Research and Special Programs Administration. This report describes (1) the agencies' chemical risk assessment activities, (2) the agencies primary procedures for conducting risk assessments, (3) major assumptions or methodological choices in their risk assessment procedures, and (4) the agencies' procedures or policies for characterizing the results of risk assessments.