Environmental Compliance

Integrating Scientific Methodology into the National Environmental Policy Act Process

The National Environmental Policy Act (NEPA) states that, to the fullest extent possible, all agencies of the Federal government shall utilize a systematic, interdisciplinary approach which will insure the integrated use of the natural and social sciences in planning and in decisionmaking which may have an impact on man's environment (42 U.S.C. 4332). The Council on Environmental Quality's (CEQ's) NEPA implementing regulations state that " Agencies shall insure the professional integrity, including scientific integrity, of the discussions and analyses in environmental impact statements" (40 CFR • 1502.24). Agencies are required to identify any methodologies used and make explicit reference by footnote to the scientific and other sources relied upon for conclusions in the statement. Discussions of methodology may be placed in an appendix. The Animal and Plant Health Inspection Service (APHIS) NEPA implementing regulations further indicate that part of their purpose is to promote "the effective, efficient integration of all relevant environmental requirements under the aegis of the National Environmental
Policy Act" (7 CFR • 372.1).

The integration of scientific methodology into the NEPA process is often a challenge because of limited data and the constraints of available methods for determining significant impact. This is most often achieved through the use of risk assessments that determine which risks pose a potential significant impact. The risk assessments may be concerned primarily with human health, nontarget species, or the affected ecosystem (an ecological risk assessment). The actual risk assessment may be quantitative if sufficient data are available for the required calculations or qualitative if the necessary data are lacking. Comparable scientific analyses of risk for each potential alternative provide a clear comparison of the alternatives from which the Administrator must decide, but quantitative data may not be available for the " no action" alternative (unlike the action alternatives).

When data are lacking or there is no widely accepted method for assessing the impact of a given action, determinations may be based on the "weight of evidence." This involves determination of the risk of an action based upon review of the available scientific data about the hazards and the likelihood of these hazards actually posing an adverse impact. The primary value of risk assessment is not in its ability to determine risk for one alternative, but instead in its ability to compare risk for different alternatives. This allows the decisionmaker to compare the relative risks of each alternative and make an informed decision based upon scientific analyses.