EPA is releasing its third list of drinking water contaminants that are known or anticipated to occur in public water systems and may require regulation. EPA will continue to evaluate and collect data on the contaminants, and determine by 2013 for some of them whether or not to propose drinking water regulations.

The contaminant candidate list (CCL 3) includes 104 chemical contaminants or groups and 12 microbes. Among them are contaminants, pesticides, disinfection byproducts, pharmaceuticals, chemicals used in commerce, waterborne pathogens and algal toxins. The agency’s selection of contaminants builds upon evaluations used for previous lists and is based on substantial expert input and recommendations from different groups including stakeholders, the National Research Council and the National Drinking Water Advisory Council, according to the agency.

EPA will make regulatory determinations for at least five contaminants in accordance with the Safe Drinking Water Act. For those CCL 3 contaminants that lack sufficient information for a regulatory determination by 2013, EPA will encourage research to provide the information needed.

The agency evaluated approximately 7,500 chemicals and microbes and selected 116 candidates for the final list based on their potential to pose health risks through drinking water exposure.

The agency considered the best available health effects and occurrence data and information to evaluate unregulated contaminants.

A draft CCL 3 was published for review and comment on February 21, 2008. EPA reviewed and analyzed the information provided in the comments in developing the final CCL 3.