nants is examined and narrowed to a preliminary CCL using simple screening criteria and expert judgment. All PCCL contaminants are next individually assessed using a “prototype” classification tool in conjunction with expert judgment to create the corresponding (and much smaller) CCL.

The committee also continues to recommend that this two-step process be repeated for each CCL development cycle to account for new data and potential contaminants that inevitably arise over time. In addition, all contaminants that have not been regulated or removed from the existing CCL should be retained automatically on each subsequent CCL. Chapters 3 to 5 of this report provide detailed descriptions, examples, and recommendations for implementing the recommended two-step approach.


As its previous reports, the promotion of public health remains the guiding principle of the committee’s recommendations and conclusions in this report. As in those documents, the committee recognizes that questions of economic impact, required technological shifts, and political orientations and concerns are all related to how safe drinking water is provided and at what cost. However, the committee has adopted an explicitly public health orientation because section 1412(b)(1)(A)(i) of the amended SDWA specifically directs the EPA administrator to identify “contaminants for listing [that], first, may have an adverse effect on the health of persons.” Further, section 1412(b)(1)(c) specifies that EPA must focus on contaminants that pose the “greatest health concern.” Therefore, in framing this report the committee has chosen to adopt an explicit public health perspective, rather than any of a number of other possible perspectives (e.g., enterprise centered, economic development, legal). The report should be read with this qualification in mind.

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