The precautionary principle in environmental science - Commentaries

Environmental Health Perspectives, Sept, 2001 by David Kriebel, Joel Tickner, Paul Epstein, John Lemons, Richard Levins, Edward L. Loechler, Margaret Quinn, Ruthann Rudel, Ted Schettler, Michael Stoto

1. Scientific studies can tell us something about the costs, risks, and benefits of a proposed action, but there will always be value judgments that require political decisions.

2. The scientific data used for making policy will nearly always be limited by uncertainty. Even the best theory and data will leave much that is not known about estimates of risks, benefits, or costs.

3. In conducting their research, scientists must make assumptions, choices, and inferences based on professional judgment and standard practices, that if not known by the public or policy makers, may make scientific results appear to be more certain and less value laden than is warranted.

4. Although there are some situations in which risks clearly exceed benefits no matter whose values are being considered, there is usually a large gray area in which science alone cannot (and should not) be used to decide policy.

5. In these gray areas, status quo activities that potentially threaten human and environmental health are often allowed to continue because the norms of traditional science demand high confidence in order to reject null hypotheses, and so detect harmful effects.

6. This scientific conservatism is often interpreted as favoring the promoters of a potentially harmful technology or activity when the science does not produce overwhelming evidence of harm.

7. The precautionary principle, then, is meant to ensure that the public good is represented in all decisions made under scientific uncertainty. When there is substantial scientific uncertainty about the risks and benefits of a proposed activity, policy decisions should be made in a way that errs on the side of caution with respect to the environment and the health of the public.

REFERENCES AND NOTES

(1.) O'Riordan T, Cameron J, eds. Interpreting the Precautionary Principle. London:Earthscan, 1994.

(2.) Freestone D, Hey E, eds. The Precautionary Principle and International Law. Boston:Kluwer Law International, 1996.

(3.) Raffensperger C, Tickner J, eds. Protecting Public Health and the Environment: Implementing the Precautionary Principle, Washington, DC:Island Press, 1999.

(4.) WHO. Electromagnetic Fields and Public Health Cautionary Policies. Geneva:World Health Organization. Available: http://www.who.int/peh-emf/publications/ facts_press/EMF-Precaution.htm [cited 5 July 2001].

(5.) Aasen S, Johnsson A, Bratlid D, Christensen T. Fifty-Hertz magnetic field exposures of premature infants in a neonatal intensive care unit. Biol Neonate 70:249-264 (1996).

(6.) U.S. EPA. Mercury Study Report to Congress. EPA 452/R-97-003, Washington, DC:U.S. Environmental Protection Agency, 1997.

(7.) Schettler T. In Harm's Way: Toxic Threats to Child Development. Boston:Greater Boston Physicians for Social Responsibility, 1997.

(8.) Abadin HG, Hibbs BF, Pohl HR. Breast-feeding exposure of infants to cadmium, lead and mercury: a public health viewpoint. Toxicol Ind Health 13:495-517 (1997).

(9.) Pohl HR, Hibbs BF. Breast-feeding exposure of infants to environmental contaminants--a public health risk assessment viewpoint: chlorinated dibenzodioxins and chlorinated debenzofurans. Toxicol Ind Health 12:593-611 (1996).