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  • Risk assessment is the systematic scientific characterization of potential adverse health effects resulting from human exposures to hazardous agents or situations.

  • Risk is defined as the probability of an adverse outcome under specified conditions.

  • Risk management refers to the process by which policy actions are chosen to control hazards.

Toxicologic research and toxicity testing conducted and interpreted by toxicologists constitute the scientific core of an important activity known as risk assessment. In 1983, the National Research Council detailed the steps of hazard identification, dose–response assessment, exposure analysis, and characterization of risks in Risk Assessment in the Federal Government: Managing the Process (widely known as The Red Book). The scheme shown in Figure 4–1 provides a consistent framework for risk assessment across agencies with bidirectional arrows showing an ideal situation where mechanistic research feeds directly into assessments and critical data uncertainty drives research. Often, public policy objectives require extrapolations that go far beyond the observation of actual effects and reflect different tolerances for risks, generating controversy.


Risk assessment/risk management framework. This framework shows, under the red highlight, the four key steps of risk assessment: hazard identification, dose–response assessment, exposure assessment, and risk characterization. It shows an interactive, two-way process where research needs from the risk assessment process drive new research, and new research findings modify risk assessment outcomes. At the start of the risk assessment process, a risk problem is formulated and provides context for the assessment (Ecology RA). (Reprinted with permission from Risk Assessment in the Federal Government: Managing the Process. Washington, DC: National Academies Press, National Academy of Sciences, 1983.)

A comprehensive framework that applies two crucial concepts: (1) putting each environmental problem or issue into public health and/or ecological context and (2) proactively engaging the relevant stakeholders, including affected or potentially affected community groups, from the very beginning of the six-stage process shown in Figure 4–2. Particular exposures and potential health effects must be evaluated across sources and exposure pathways and in light of multiple end points, and not the current general approach of evaluating one chemical in one environmental medium (air, water, soil, food, and products) for one health effect at a time.


Risk management framework for environmental health from the U.S. Commission on Risk Assessment and Risk Management. The framework comprises six stages: (1) formulating the problem in a broad public health context; (2) analyzing the risks; (3) defining the options; (4) making risk reduction decisions; (5) implementing those actions; and (6) evaluating the effectiveness of the actions taken. Interactions with stakeholders are critical across all the stages and thus have been put at the center of the framework.


The phrase characterization of risk...

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