Overview of the CCL 4 Approach
In selecting contaminants for the CCL 4, EPA:
- Carried forward CCL 3 contaminants (minus those with regulatory determinations) to the Draft CCL 4.
- Sought and evaluated nominations from the public for additional contaminants to consider in May 2012.
- Evaluated any new available data for those contaminants with previous negative regulatory determinations from CCL 1 or CCL 2 for potential inclusion on the Draft CCL 4.
- Considered public and Science Advisory Board (SAB) comments and evaluated the data and information provided by commenters in selecting the Final CCL 4.
EPA carried forward all contaminants listed on CCL 3 to the Draft CCL 4 with the exception of perchlorate, for which the agency made a positive regulatory determination, and the five CCL 3 contaminants with preliminary regulatory determinations at that time, pending their final regulatory determinations.
EPA evaluated the nominated contaminants and contaminants with previous negative regulatory determinations utilizing the best available health effects and occurrence data and the same process for screening and scoring contaminants that was used for CCL 3.
The Agency reviewed the data provided by the nominators and collected additional data for the nominated contaminants and contaminants with previous negative regulatory determinations, when it was available, from both CCL 3 data sources that had been updated and from new data sources that were not available at the time of CCL 3.
EPA requested comment on the Draft CCL 4 and how to further improve upon the selection process developed for CCL 3 as a tool for future CCLs. EPA considered all public comments and evaluated data and information provided by commenters in determining the Final CCL 4.