Expert Report

Science and Decisions: Advancing Risk Assessment (2009)

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Each report is produced by a committee of experts selected by the Academy to address a particular statement of task and is subject to a rigorous, independent peer review; while the reports represent views of the committee, they also are endorsed by the Academy. Learn more on our expert consensus reports.

Risk assessments evaluate potential adverse health effects posed by harmful chemicals found in the environment and inform a range of decisions from protecting air and water to ensuring food, drug, and consumer product safety. Unfortunately, the risk assessment process is bogged down by challenges to its timeliness and credibility, a lack of adequate resources, and disconnects between the available scientific data and the information needs of decision-makers. In light of these challenges, EPA asked the National Research Council to conduct an independent study on improvements that could be made to risk assessment. The report concludes that EPA's overall concept of risk assessment, which is based on the National Research Council's 1983 "Red Book," should be retained but that a number of significant improvements are needed to advance the use of risk assessment in decision making. Recommended changes include greater attention to planning and problem formulation, improved stakeholder involvement, and a better match of the level of detail needed in a risk assessment to the questions that should be addressed. The report also concludes that a unified approach to cancer and noncancer dose-response assessment is scientifically feasible and should be pursued.

Key Messages

  • Addressing uncertainty and variability is critical for the risk-assessment process.
  • Design of Risk Assessment should be reinforced by the up-front involvement of decision-makers, stakeholders, and risk assessors, who together can evaluate whether the design of the assessment will address the identified problems.
  • Uncertainty is inherent in all stages of risk assessment, and EPA typically relies on assumptions when chemical-specific data are not available.
  • A consistent approach to risk assessment for cancer and noncancer effects is scientifically feasible and needs to be implemented.
  • Although cumulative risk assessment has been used in various contexts, there has been little consideration of nonchemical stressors, vulnerability, and background risk factors.
  • Cumulative human health risk assessment should draw greater insights from ecologic risk assessment and social epidemiology, which have had to grapple with similar issues.
  • Improving technical analysis entails the development and use of scientific knowledge and information to promote more accurate characterizations of risk.
  • Improving utility entails making risk assessment more relevant to and useful for risk-management decisions. The committee proposes a framework for risk-based decision-making.
  • There is a need for simplified risk-assessment tools (such as databases, software packages, and other modeling resources) that would allow screening-level risk assessments and could allow communities and stakeholders to conduct assessments and thus increase stakeholder participation.