Precaution in US environmental law

Robert Percival recently posted "Risk, Uncertainty and Precaution: Lessons from the History of US Environmental Law", discussing, among other things, the history of the precautionary approach in American environmental law, including its acceptance by some federal courts in the 1970s. The abstract:

The DC Circuit Court of Appeals upheld the EPA's
precautionary standard limiting gasoline lead
in Ethyl Corporation v. EPA (541 F.2d 1 (1976))

Globalization and expanding world trade are creating new pressures to harmonize environmental standards. Countries increasingly are borrowing legal and regulatory policy innovations from one another, moving toward greater harmonization of regulatory policies. Regulatory policy generally seeks to prevent harm before it occurs, but the reality is that it usually has been more reactive than precautionary, responding only after harm has become manifest. As regulators seek to improve their responses to new and emerging environmental risks, it is useful to consider what lessons can be learned from past experience with regulatory policy. This chapter reviews controversies over regulatory policy through the lens of history. It discusses the precautionary principle and why it is valuable even if it does not purport to answer the question of how stringent regulatory policy should be. It also considers recent studies that assess whether regulatory policy is more precautionary in the United States or the European Union [see, e.g., here] and why it is difficult to make confident, comparative conclusions. The chapter then examines the history of how precaution has been incorporated into U.S. environmental law. It demonstrates that, despite the law’s promise to prevent harm before it occurs, regulatory policy has been largely reactive, concentrating primarily on highly visible problems only after harm has become manifest. After reviewing the state of contemporary regulatory politics in the U.S., the chapter concludes by analyzing lessons that can be learned to improve future regulatory policy.