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To Ban or Not to Ban

Gail Charnley

Pandora's Poison: Chlorine, Health, and a New Environmental Strategy. Joe Thornton. xii + 599 pp. MIT Press, 2000. $34.95.

Quantitative risk assessment uses scientific data along with science-based judgment and assumptions to draw conclusions about the nature and likelihood of risks. Those conclusions can be useful for comparing risks, for setting risk- management priorities and for deciding what are the best ways to limit risks. But because both science and judgment play important roles, risk assessment is controversial. Often the controversy arises from what we do not know and from what risk assessments cannot tell us, because our knowledge of human vulnerability and of environmental impacts is incomplete. Nonetheless, because of its scientific underpinnings, risk assessment generally constitutes the vehicle for including science in environmental health risk-management decision-making.

Risk-management decision-making, of course, is not based solely on the results of risk assessments; political, cultural, technical, economic, feasibility and many other considerations also play important roles. Together, our environmental laws and the efforts of governments, businesses, citizens and municipalities are responsible for giving us the cleanest environment we have had in the United States in 30 years. Since the industrial revolution began, life expectancy has increased by 30 years. Countries that lack environmental laws like ours lag way behind us in terms of environmental quality and public health improvements.

Pandora's Poison challenges the chemical-by-chemical, environmental-medium-by-environmental-medium, risk-by-risk approach that current regulation takes to controlling chemical exposures separately in air, water, food, soil, the workplace and consumer products. That fragmented strategy arose because of divided jurisdictions in Congress, which led to separate federal laws that in turn created separate regulatory agencies and programmatic fiefdoms within agencies. Thornton tells us that a "witch's brew of toxic, persistent pollutants has come to blanket the entire planet" because the "apparently sophisticated environmental laws of industrialized countries" have "failed to halt the tide of contamination." The fatal flaw in our environmental laws, according to the author, is their reliance on risk assessment. In addition to addressing chemicals one at a time, risk assessment is problematic because it fails to address ethical and moral issues of safety and because risk estimates are speculative and untestable.

Well, yes, risk estimates are just that—estimates, of what might occur under certain sets of assumptions, and as such they are meant to provide useful input to decision-making about the best ways to limit risks. They are not designed to be testable scientific predictions of actual risks or the sole determinants of risk-management decisions. Risk assessment does not address ethical issues of safety—people do. People make political and moral decisions about how much risk is acceptable. Those who find such decisions unacceptable should not condemn risk assessment as a practice; instead, those who make the decisions, and the legal and statutory basis that guides them, should be held responsible.

Pandora's Poison also criticizes calls for a greater role for science in environmental health protection; Thornton believes that a better balance between scientific information and judgment is needed instead. It is true that educated nonscientists (for example, lawyers and legislators) sometimes confuse science and judgment by assuming that if only the "right" science were known or generated, the "right" answer or course of action would become apparent. If only we relied on "good" science, we would know what is safe and what is not. This belief arises in part from a misunderstanding of science and in part because the legal tradition in the United States relies heavily on establishing a factual basis for decision-making. The factual basis for a risk-management decision is highly valued because, in the absence of a complete factual basis or record, decisions are easily challengeable in court. As a consequence, the judgment or less factually based component of risk-management decision-making is perceived as being less highly valued.

As the solution to regulatory fragmentation and the alleged environmental catastrophe it is supposed to have produced, Pandora's Poison recommends a holistic risk-management "paradigm" that eschews risk assessment. The paradigm is based on banning chlorine-containing chemicals and the products they are found in. Thornton evaluates organochlorine exposure and toxicity data and finds that potential risks to public and environmental health from those compounds are unacceptably high. In other words, he performs a risk assessment of organochlorines and proposes banning them—along with risk assessment—as a risk-management solution.

Pandora's Poison asserts that environmental chlorine exposures "may be linked" to the incidence of a variety of health and environmental problems and "may be an important factor" in the increases in many of those problems. Evidence that something may or may not be linked to something else seems hardly to justify a call for banning an entire class of chemicals and, by extension, the huge array of products and processes dependent on them. Many of the effects of concern cited in the book—immune suppression, infertility, developmental problems—have so many other causes that even if they are increasing (and there is certainly no agreement that that is the case), a more reasonable public health approach might be to address the causes we all agree on and know we can have an impact on with considerably less societal investment (for example, correcting nutritional deficiencies and improving prenatal care).

A number of organizations have recommended moving away from relying solely on chemical-by-chemical regulation. In 1997, the Presidential/Congressional Commission on Risk Assessment and Risk Management acknowledged that the chemical-by-chemical approach had established an important floor for restricting chemical exposures and recommended a more holistic, broad-based risk-management philosophy in order to achieve the next level of environmental protection. The U.S. Environmental Protection Agency (EPA) recommends putting threats in their larger ecological contexts instead of addressing individual chemicals; currently the EPA is developing a cumulative-risk framework that is population-based and starts with communities to determine what chemicals and other stressors are affecting public health.

Pandora's Poison lacks broad appeal and credibility because it dismisses all aspects of current thinking about environmental protection and public health improvement as based solely on standard setting using oversimplified approaches to quantitative risk assessment; it doesn't acknowledge the extensive environmental achievements that clearly have been made since Rachel Carson, partly as a result of regulation and standard setting; it doesn't acknowledge the integrated, holistic risk-management strategies proposed and used by others; and it fails to demonstrate how a risk-management strategy that relies on banning chlorine could be applied usefully to other environmental and public health improvement issues.—Gail Charnley, HealthRisk Strategies, Washington, DC

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