The 1991 Lead/Copper Drinking Water Rule and the 1995 Decision Not to Revise the Arsenic Drinking Water Rule: Two Case Studies in EPA's Use of Science

This paper discusses EPA's acquisition and use of science in two decisions under the Safe Drinking Water Act: the 1991 revision of the lead drinking water regulations and the 1995 decision to pursue additional research instead of revising the arsenic in drinking water standard. In the first case, a committed band of policy entrepreneurs within EPA mobilized and supplemented scientific information which had accumulated in the agency's air program to force lead in drinking water up the agency's regulatory agenda. In the minds of senior EPA decisionmakers, there was adequate science to justify making the lead in drinking water regulation more stringent; the critical question was "how far to go" in terms of regulatory compliance expenditures. To the extent that the agency's use of science increased the regulatory benefits estimate, it could rationalize more stringent and costly regulations. In the case of arsenic in drinking water, not only the scientific uncertainties in estimating the health risks but also the regulatory compliance costs, the distribution of those costs, and the presumed public health impacts of delay were important in the decision to pursue additional research on the health risks of arsenic. However, because EPA decisionmakers have failed to articulate what they consider to be compelling scientific evidence to justify departing from default risk assessment procedures in this case, it seems less likely that future research will facilitate future decision-making. Both cases illustrate impediments to the generation of scientific data needed for regulatory decision-making, the potential for scientific information to be distorted in or omitted from the regulatory decision-making process, and the key roles played by intermediaries between scientists and decisionmakers within EPA.