1. INTRODUCTION


The Commission on Risk Assessment and Risk Management was mandated by Congress in the 1990 amendments to the Clean Air Act to address risks that are regulated under the many laws aimed at protecting the environment and protecting the health and safety of the American people from potentially dangerous exposures to chemicals and other hazardous substances and objects in air, water, food, the workplace, and consumer products. Of the 10 members of the Commission, 3 were appointed by the president, 6 by the majority and minority leaders of the House and Senate, and 1 by the president of the National Academy of Sciences.(1) The Commission's mandate(2) is summarized in the following phrases:

  • Assess uses and limitations of risk assessment.
  • Evaluate exposure scenarios for risk characterization.
  • Determine how to describe and explain uncertainties.
  • Enhance strategies for risk-based management decisions.
  • Review desirability of consistency across federal programs.
  • The Commission was also asked to comment on the conclusions of Science and Judgment in Risk Assessment (NRC 1994a) (see appendix A.3) and to make recommendations about peer review.

    Congress decided to create the Commission when agreement could not be reached, during drafting of the 1990 Clean Air Act Amendments, on the best way for the U.S. Environmental Protection Agency (EPA) to determine whether any significant risks to human health will remain after technology-based controls are implemented to reduce hazardous-pollutant emissions from stationary sources and, if so, what to do about those residual risks. There was disagreement about the risk-assessment techniques and assumptions that should be used to estimate residual risks, about the benchmarks that should be used to distinguish between negligible and unacceptable risks, and about the risk-management methods that should be used to mitigate unacceptable risks. But the Commission's mandate was not restricted to evaluating air pollution, the particulars of the Clean Air Act, or the EPA. Rather, it was limited to "cancer and other chronic human health effects," so we did not address environmental problems, such as global climate change, ozone depletion in the stratosphere, or protection of wetlands and other habitats. We do note, however, that human health depends on a healthy environment, that the general approaches of health risk assessment are applicable to ecological risk assessment, and that benefit-cost analyses should assess all benefits, not just human-health benefits.

    Through its deliberations, the Commission developed a shared vision of sustainable goals for our environment, our economy, and our society. Like the National Commission on the Environment (1992) and the President's Council on Sustainable Development (1996), we seek a convergence of economic and environmental goals and actions. We recognize that special sensitivity is required to encompass the diverse socioeconomic status and cultural practices of this nation. We seek a comprehensive, risk-based approach that puts specific actions in a public-health and ecological context.

    As a result of public recognition of environmental problems and translation of that recognition into effective action, tremendous progress has been achieved during the last 25 years in improving air quality, water quality, safety at work, safety of consumer products (including drugs and foods), testing of new chemicals before they are introduced into commerce, cleanup and disposal of hazardous wastes, and scientific study of health effects and ecological effects of chemicals, radiation, and microorganisms. Improvements in public health historically have come primarily from environmental interventions, such as proper waste disposal and hygiene, quarantines, clean water, and vaccines. Although many federal environmental laws share a primary goal of protecting the public's health and the environment, most environmental statutes have been media-specific and have relied on regulatory approaches rather than public-health approaches.

    We know that the gains of the last 25 years can be sustained only by continued action, especially as the economy and the population grow and new technologies are introduced, and we believe that the effort to sustain them will be most effective if regulatory and public-health agencies work together.

    Risk is a combination of the probability of an event--usually an adverse event--and the nature and severity of the event. We deal with risks all the time in everyday life--risks to our health, our environment, our pocketbooks, our social relationships. Risk is time-related, from immediate consequences of various actions or lack of action to consequences over a lifetime for an individual and much longer periods for the whole society or the planet. We make decisions to avoid risks, to reduce risks, to reduce the consequences of events, and to insure against the financial consequences of risks. We tend to downplay some risks; we find others frightening. Of course, people vary in those assessments, and their actions or concerns tend to vary accordingly. Often, the people who face specific risks are different from the people who benefit from the events involved in the risks, leading to conflict and litigation over proposed actions. Risk assessment itself has become controversial because of its important role in the protection of human health and the environment.

    A generally accepted framework and nomenclature for health risk assessment was established in 1983 by a National Academy of Sciences committee report, Risk Assessment in the Federal Government: Managing the Process (NRC 1983). The now universally recognized four-step framework for characterizing the likelihood of adverse health effects from particular chemical exposures is described briefly below and shown in the context of scientific issues and regulatory impact in figure 1.1.

    Figure 1.1 Elements of risk assessment and risk management

    Source: Science and Judgment in Risk Assessment (NRC 1994a). Reprinted with permission.

  • Hazard identification: Determine the identities and quantities of environmental contaminants present that can pose a hazard to human health.

  • Dose-response assessment: Evaluate the relationship between contaminant exposure concentrations and the incidence of adverse effects in humans.

  • Exposure assessment: Determine the conditions under which people could be exposed to contaminants and the doses that could occur as a result of exposure.

  • Risk characterization: Describe the nature of adverse effects that can be attributed to contaminants, estimate their likelihood in exposed populations, and evaluate the strength of the evidence and the uncertainty associated with them.
  • The Commission was directed to focus on what Congress called "chronic health effects", meaning effects that do not occur immediately--like injuries from falling off a construction platform--but that are the cumulative result of repeated exposures that might take months, years, or decades to become manifest as health problems. Risks from chronic exposures arise from activities associated with the use and production of food, energy, industrial and consumer goods, and from the wastes produced through daily living. We recognize that voluntary uses of specific consumer products are also major contributors to death and poor health. Cigarette-smoking leads the list by a wide margin, accounting for an estimated 400,000 deaths every year (McGinnis and Foege 1993). Use of alcoholic beverages accounts for about 100,000 deaths, and motor-vehicle collisions for about 25,000 deaths. As many as 60,000 deaths per year are estimated to be attributable to airborne fine particles. Many activities individually contribute little to overall public-health risks but substantially when viewed collectively. For example, 60,000 deaths per year have been attributed to occupational and environmental chemical exposures of all types.

    Of all causes of death, the most salient for most people is cancer; it is important to recognize that cancer has multiple causes and is not a single disease. However, cancer is not the only cause of health concerns associated with environmental pollutants. Reproductive impairments, birth abnormalities, asthma and other forms of airway hyperactivity, and effects on all the organ systems of the body warrant serious attention from a risk-management perspective. Even if those health effects have modest impacts on mortality, they are important determinants of our quality of life.

    Risk assessment goes beyond scientific observations of exposures and effects in people, animals, or test systems to try to answer social questions about what is unsafe. There is a difference between what can be studied experimentally or be observed directly and what represents policy-driven extrapolation based on scientific inferences and many assumptions. The 1994 National Research Council report Science and Judgment in Risk Assessment captured this combination of science and values in its title.

    We face a huge challenge to manage comprehensively the health risks associated with the vast array of pollution-generating activities in this country. Our regulatory agencies are expected to control, down to an extremely low level, the potential cancer risks, for example, associated with each of those individual activities; a limit of less than 1 extra cancer death from a particular chemical per million persons exposed over a 70-year lifetime is generally used for screening purposes and when exceeded, might serve as a justification for seeking exposure monitoring data to more accurately characterize risks. Risk criteria used in regulating occupational exposure to specific chemicals often correspond to about 1 extra cancer death out of every 1,000 workers exposed over a working lifetime. For noncancer risks, regulatory agencies aim to reduce exposures to below presumed thresholds for adverse effects.

    As directed by Congress and reinforced by the Clinton Administration, we have framed our analyses and recommendations from the perspective of risk management. How do we use the tools of risk assessment and of economic analysis and consider social and cultural information to make better, more-efficient, more-understandable, and less-costly decisions about reducing risks that are judged to be too high? How do we compare risks and risk-reduction actions of various kinds to determine which deserve higher priority? What are the community, public-health, and environmental contexts for formulating a particular problem, characterizing its risks, deciding what to do about it, and evaluating the impact of actions taken? It is crucial to reach out to affected parties and communities to obtain knowledge about the nature of past and present exposures and to understand their concerns and perceptions about the risks under discussion and related risks. Communication about risks is a two-way process.

    To address those questions, the Commission proposes a comprehensive risk-management framework for making decisions about reducing risks to public health and the environment. The process includes detailed consideration of risk and cost and provides a context for social and cultural considerations. One salient feature of the framework is its explicit involvement of stakeholders in decisions about how to reduce the risks that affect them--through consensus or despite disagreement--depending on the circumstances. Another salient feature is the integrated, multimedia approach the framework takes to address multiple risks instead of individual risks.

    This report is the product of the Commission's deliberations and evaluations since May 1994 and constitutes a response to concerns of those who provided testimony before the Commission(3) and issue papers prepared for the Commission by several experts.(4) Section 2 describes the framework and its application, setting the stage for the rest of the report. Sections 3 and 4 provide guidance on how to approach the risk and cost components of the framework. Section 5 addresses ways to improve risk communication and risk management. Section 6 provides recommendations for specific federal regulatory agencies and programs.

    This report is a draft intended to elicit public review and comment. The draft and the reports abstracted in appendix A.5 are available from the internet at http://www.riskworld.com. The Commission welcomes written comments addressed to its office at 529 14th St. NW, Suite 452, Washington, DC 20045--preferably by July 17, so that they can be considered in a public hearing on July 23 in Boston, but as late as August 9, so that they can be considered in the preparation of the final report. The Commission's final report will be issued in October 1996 and will be followed by additional hearings and presentations at meetings.


    1Biographies of Commission members are provided in appendix A.1.

    2A copy of the Commission's mandate is included as appendix A.2.

    3A list of the persons who testified at Commission meetings is included as appendix A.4.

    4Abstracts of the issue papers prepared for the Commission are included as appendix A.5.




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