EPA is researching and evaluating a list of 51 unregulated, new or emerging drinking water contaminants for possible regulation. The Contaminant Candidate List (CCL) process was established by the 1996 Amendments to the Safe Drinking Water Act (SDWA) as a tracking and priority-setting mechanism to determine if new regulations are needed to protect drinking water safety.
Unregulated contaminants that are known or anticipated to occur in drinking water comprise the list. The SDWA requires EPA to conduct extensive research into the occurrence and health effects of the listed contaminants before issuing new regulations or standards. With this action, EPA is releasing the second CCL which carries over a number of contaminants from the first CCL and announcing plans to expand and strengthen the contaminant candidate listing process.
The SDWA directs EPA to periodically publish a list of contaminants that "at the time of publication, are not subject to any proposed or promulgated national primary drinking water regulation, which are known or anticipated to occur in public water systems, and which may require regulation.
In July 2003, EPA removed contaminants from the first CCL after the Agency concluded that sufficient data and information was available to determine not to regulate nine contaminants.
EPA is publishing both a final CCL and an update on the agency's work to improve the CCL selection process. In addition, EPA is reviewing more contaminants for inclusion on the third CCL and is working to implement a more transparent system for selecting contaminants.
EPA's new approach will produce a more comprehensive CCL because the process will address a wider range of information and screen contaminants more systematically, as was recommended by the National Academy of Sciences and the National Drinking Water Advisory Council.