Panel Calls for Changes to EPA's Risk Assessments
EPA's process of generating risk assessments -- which estimate the potential adverse effects posed by harmful chemicals found in the environment in order to protect public health -- is bogged down by unprecedented challenges, and as a decision-making tool it is often hindered by a disconnect between available scientific data and the information needs of officials, according to a new report from the National Research Council. EPA's risk assessment process should be streamlined to ensure the appropriate use of available science, technical accuracy, and tailoring to the specific needs of the problem.
The risk assessment process entails four steps -- hazard identification, exposure assessment, dose-response assessment, and risk characterization -- which were described in a 1983 National Research Council report known as the Red Book. After a risk assessment is complete, officials and regulators use it to decide how to protect the public from exposure to toxic substances. However, the challenges of risk assessment have become increasingly complex. As knowledge of environmental contaminants and potential health impacts advances, EPA must address issues of multiple exposure, multiple risks, and susceptibility of different populations. Recognizing this, the agency asked the Research Council to identify improvements it could make to enhance risk assessment. In turn, the committee that wrote the report presented recommendations and a proposed framework for risk-based decision making to provide a template for risk assessment in EPA and strengthen the scientific basis, credibility, and effectiveness of future risk management decisions.
The committee found that EPA is struggling to keep up with demands for hazard and dose-response information and is challenged by a lack of resources. For example, the risk assessment for trichloroethylene, a chemical that is linked to cancer, has been under development since the 1980s and is not expected until 2010. However, state and federal officials often must continue to make risk management decisions in the absence of completed risk assessments. If this practice continues, the value and credibility of risk assessment will erode, the committee stressed. Perfection in scientific knowledge is unattainable; therefore, risk assessment should incorporate the best available scientific information and reasonably capture uncertainties in information so it is still useful for officials.
EPA should focus more attention on the formative stages of risk assessment, specifically on planning, scoping, and problem formulation, which have been applied inconsistently, the committee said. This includes defining a clear set of options for consideration and involving decision makers, stakeholders, and risk assessors upfront to evaluate whether the design of the assessment will address the problems.
To this end, the committee proposed that EPA adopt an expanded risk assessment framework that has the same core as the Red Book model but differs in its preliminary and final steps. The three-phase framework begins with enhanced problem formulation and scoping, in which risk management options and the types of technical analyses needed to evaluate and discriminate among the options are identified. The second phase involves planning, hazard identification, exposure assessment, risk characterization, and deciding whether the assessment is appropriate and allows discrimination among risk management options. The final phase examines the relative health or environmental benefits of the proposed risk management options for the purpose of reaching a decision.
The committee also recommended that EPA adopt a unified approach for the dose-response step of risk assessment, which estimates the amount of a chemical that would lead to an adverse health effect.
Additional information on the report, Science and Decisions: Advancing Risk Assessment, can be found at http://www.nap.edu/catalog.php?record_id=12209.