Effective last month, the EPA published the final Drinking Water Contaminant Candidate List 4 (“CCL 4”). CCL 4 is the final list of contaminants which are currently unregulated, but are otherwise known or anticipated to occur in public water systems and may require future regulation under the Safe Drinking Water Act (“SDWA”). The final CCL 4 includes 97 chemicals or chemical groups and 12 microbial contaminants. Of note, the CCL 4 list includes: 1,4-Dioxane, Perfluorooctanesulfonic acid (“PFOS”), Perfluorooctanoic acid (“PFOA”), Ethylene Glycol, and methyl bromide, along with the metals cobalt, manganese, and vanadium.

Now that the CCL 4 has been published, EPA must determine whether or not to regulate at least five contaminants from the CCL 4 in a separate process called a Regulatory Determination. The Agency will make Regulatory Determinations for the CCL 4 contaminants for which there are sufficient health effects and occurrence data and which present the greatest public health concern. The Regulatory Determination process is currently in the early stages of internal agency evaluations. It is worth noting that Exhibit 2 (in Section V) of the Final CCL 4 Federal Register notice categorizes the CCL 4 contaminants based on the availability of their occurrence data and health assessments. Because the contaminants in Group A of Exhibit 2 have nationally representative finished drinking water data and a peer reviewed health assessments, those Group A contaminants would seem more likely to be subject to further assessment under the upcoming Regulatory Determination process due to the existence of the data. Further updates will be posted once more information becomes available on the upcoming Regulatory Determination process.