Implementing the precautionary principle.

The precautionary principle can be found in international treaties that protect human health and the environment from a variety of pollutants and perturbations. One of the earliest forms of the precautionary principle was used in the 1980s in Europe to protect the North Sea. In 1992, the Rio Declaration specifically included the precautionary principle in calling on nations to protect the environment. The US articulation that best embodies this approach to environment and human health protection is the Wingspread statement: 'When an activity raises threats of harm to human health or the environment, precautionary measures should be taken, even if some cause and effect relationships are not fully established scientifically.' The key element is the matter of acting in the face of uncertainty. Applications of the precautionary principle are not, however, new to US environmental policy and management. The present paper uses case studies to examine the application of the precautionary principle to environmental decisions. These cases range from ecosystem protection on the Charles River, Massachusetts, to the effort to prevent computer crashes at the end of the year 2000. These cases deal with the problem of uncertainty, whether concerning the cause, effect, systemic condition or multiple factors. Uncertainty represents one of the features that provoke controversy over these issues and the precautionary principle.