Industrial sources of benzene exposure?

actions (e.g., exposure assessments, epidemiologic investigations, exposure registries, surveillance) that should be pursued in communities. Even with the efforts to measure exposure, the important question about latent, adverse health effects remains unanswered. As public health professionals in environmental health committed to protect the health of communities living near hazardous waste sites, we therefore strongly disagree with the authors' statement that "No further assessment of the health risks is needed." Legator and Strawn also make two other points to which we wish to respond. They state "If information on each site were available in sufficient detail, populations from exposed communities could be aggregated or combined. Unfortunately, the data that would help determine the multiple sites for which similar effects could be anticipated does not yet exist." The ATSDR agrees with the approach of combining populations from sites with reasonably common characteristics; this is the exact approach taken in our National Exposure Registry program (8). As an example, the ATSDR Subregistry of Persons Exposed to Trichloroethylene consists of a registry of about 5000 persons in 13 communities. Chemical-specific exposure subregistries provide ATSDR with health information on persons with common chemical exposures and also provide a means for communicating health information back to the registrants. In addition, more recently, ATSDR has developed the database necessary to combine site-specific information. The database is called HazDat. It contains all the environmental contamination, toxicology, and human health effects data from about 1300 Superfund sites. Recently, in conjunction with four state health departments, we conducted a study of lead exposure and toxicity in four different populations that were identified through use of HazDat. We anticipate releasing HazDat to the public later this year. Ascertaining the dangers to public health of hazardous waste sites, together with implementing public health actions to protect against the effects of hazardous substances, is a challenging responsibility. The ATSDR's public policies and public health practices must be based on sound scientific principles and data. This must involve the communities affected by releases from waste sites and other sources of hazardous substance releases. We believe the statutory mandates in the Compre-hensive Environmental Response, Comp-ensation, and Liability Act that bear on public health are consistent with sound public health practices. The translation of these mandates into actions, to some extent in ways inferred by Legator and Strawn, is ATSDR's challenge. We believe we have made progress, but much awaits.