for people living near the site (EPA, 1989b). Sampling data are used to model the potential exposures of nearby residents, although the models employed in these assessments have not been adequately validated. The lack of sound exposure data for populations living near hazardous-waste sites not only undermines the capacity of federal agencies and other investigators to conduct epidemiologic studies, but it impedes the ability of Superfund managers to assess the public health impact of hazardous-waste-site exposures.
The original CERCLA legislation also created a new public health agency to deal with the human health effects of hazardous wastes: the Agency for Toxic Substances and Disease Registry (ATSDR), within the U.S. Public Health Service. Under CERCLA, EPA is the regulatory agency that administers Superfund, while ATSDR is the non-regulatory public health agency. ATSDR depends on EPA to endorse its funding requests, and EPA has initial approval over ATSDR's annual appropriation (Siegel, 1990). Although ATSDR was authorized by CERCLA in 1980, it was not until 1983 that it was formally established by the U.S. Public Health Service, following a lawsuit by the Environmental Defense Fund, the Chemical Manufacturers Association, and the American Petroleum Institute (Siegel, 1990). By the time Superfund was due for reauthorization in 1985, ATSDR—crippled by this late start, low budgets, and a lack of staff positions—still did not have a clear agenda and work plan and had not produced any significant work on the health aspects of hazardous-waste sites.
Although Congress was sharply critical of the early failure of the Superfund program to address the health effects of hazardous wastes, Congress in fact may have contributed to this problem by creating ATSDR (without authorization of staff and fiscal support adequate to influence the remediation process), thereby achieving the unintended effect of appearing to absolve EPA of the need to directly incorporate public health considerations into site assessments. Nevertheless, Congress attempted to resolve this problem with SARA. EPA was directed to revise its site evaluation process, and Congress gave new prominence and responsibility to ATSDR, which was directed to produce public health assessments of all Superfund sites proposed for the NPL, and for other sites in response to public petition. In addition, ATSDR was required to establish a priority list of hazardous substances found at CERCLA sites, to produce toxicologic profiles for each substance on this list, and to conduct research on the health effects of hazardous substances and hazardous-waste sites (P.L. 99-499).
SARA defined ATSDR's health assessments to include:
preliminary assessments of the potential risk to human health posed by individual sites and facilities, based on such factors as