This morning, the U.S. Environmental Protection Agency announced a move that could be another step in the long process of regulating water pollution related to C8 and other perfluorinated chemicals.

EPA released the final version of “Contaminant Candidate List 3,” or a collection of chemicals that aren’t currently regulated, but are believed to be in our drinking water and might need limits set under the Safe Drinking Water Act.

This list itself is here, and there’s tons more information about the selection process here.

For folks who are concerned about PFCs, there’s big news here … The draft CCL3, released in February for public comment, included perfluorooctanoic acid, also known as PFOA or C8. But, that draft list did not include perfluorooctanyl sulfate, or PFOS.

The final list, though, includes both PFOA and PFOS.

Under the law, EPA is required to make regulatory determinations — decide whether limits are needed — for at least five of the chemicals on this list over the next five years.

Here’s a quick reminder of the difference between PFOA and PFOS, provided by the Environmental Working Group’s PFC Dictionary:

• PFOA: Perfluorooctanoic acid. Breakdown product of fluorotelomers and backbone of many DuPont products. Also used as a surfactant to produce PTFE, the Teflon in pans. Sometimes called C8.

PFOS: Perfluorooctanyl sulfate. Breakdown product of fluorotelomers that are based on 3M chemistry.

In a Federal Register notice, EPA said it did not include PFOS in the draft list in large part because of the industry’s “voluntary phase-out” program. But, EPA said, agency officials have “evaluated new information” that indicates a potential for PFOS to occur in public drinking water supplies. Based on this, and on “existing data on environmental persistence, and toxicity in animal studies” EPA concluded that PFOS “may require regulation.

EPA also said:

A number of important studies are underway, and the agency continues to participate in research regarding the toxicity of related perfluorochemicals, as well as research to help identify routes of human exposure. EPA is evaluating additional research and has not made any definitive conclusions on the risk assessment at this time.

EPA published a draft risk assessment on PFOA in 2006, but has never finalized the document. In the final days of the Bush administration, EPA also published new health advisories for drinking water contaminated with these chemicals, but those advisories do not consider the long-term threat of drinking C8-polluted water.

Also, EPA noted that some public commenters urged the agency to include other perfluorinated chemicals for potential regulation. EPA responded:

the Agency had only limited data on the potential occurrence of these compounds and potential adverse health effects … The agency will continue to evaluate perfluorinated compounds to ascertain whether they possess similar toxicological properties and if they are anticipated or known to occur in public water systems.

However, EPA also noted that the agency’s own Science Advisory Board commented that:

… perfluorochemicals may be a class of contaminants that the agency should consider as a group based on their similar structures and chemical makeup.