The Precautionary Principle

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The precautionary principle advocates common sense. This principle states that evidence of harm, rather than definitive proof of harm, should prompt policy action.

The precautionary principle allows scientifically sound and ethical decisions to be made on environmental and public health problems. When scientific uncertainty is likely to persist, the principle emphasizes the need for research paradigms that contribute to "strength of the evidence" assessments of the plausibility of health effects.

In 1998, a group of scientists, environmental activists, lawyers, and scholars met together in Racine, Wisconsin, to hone the definition of the precautionary principle as a new approach to thinking about environmental regulations and the evaluation and control of toxic chemicals. The resulting Wingspread Consensus Statement on the Precautionary Principle states that “when an activity raises threats of harm to the environment or human health, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.”

The precautionary principle holds that when significant risks to public health are suspected, efforts should be made to reduce those risks, when possible, even when scientific knowledge is inconclusive, and to seek alternatives. The principle critically shifts the burden of proof from the general public to the initiator of that public health or environmental risk. Instead of the public having to show they have been harmed, the initiator has to show that the activity, process, or chemical exposure is likely harmless.

Environmental research on health-related issues can contribute to the body of evidence used in these decisions. Exposure studies are especially critical for assessing plausibility (without exposure to a causal agent, there is no health effect). These studies are prerequisite to health studies and identify preventable exposures that could be reduced by precautionary policies, even in the absence of conclusive evidence of harm.

The precautionary principle, which originated in the environmental movement, has caught fire in the breast cancer movement, too. “For decades we have been engaged in an uncontrolled experiment with synthetic hormones and carcinogens in air, water, and everyday products,” says Dr. Julia Brody, executive director of Silent Spring Institute. “Whenever we have strong evidence that a harmful link exists, we must take steps to protect people’s health. We should not wait for science to provide definitive proof that such chemicals are contributing to the high rates of breast cancer and other diseases. Waiting, without action, can jeopardize our lives and those of future generations.”

For Further Information

FAQs: The Precautionary Principle

The Science and Environmental Health Network has created an excellent resource on the precautionary principle. To learn more, click here.