Underground plumes of the toxic “forever chemicals” known as PFAS flowing from Department of Defense installations are “in the proximity” of nearby drinking water supplies, according to a DOD report. 

The report, required by Congress, found plumes of PFAS flowing from 245 of 275 DOD installations were close to groundwater aquifers that are used as primary or secondary drinking water sources. 

To conduct the report, officials used DOD and Environmental Protection Agency data to determine whether military bases with PFAS contamination were “in the proximity” of community drinking water wells, intakes, sole source aquifers and private domestic wells. 

The report did not disclose how the DOD determined that wells were “in the proximity” of bases or whether these wells were actually contaminated. 

“Hydrology does not respect political boundaries,” said EWG’s Senior Policy Analyst Jared Hayes. “This troubling report suggests that DOD’s PFAS plumes have contaminated far more drinking water than was previously understood.”

PFAS plumes could be threatening aquifers at hundreds of other bases. But the DOD has so far only looked at 275 bases where the second stage of its cleanup process has been initiated, according to the report. PFAS contamination has been confirmed at 455 bases, and hundreds of other bases are still being evaluated, records show. 

To date, the Pentagon has provided 53 communities with alternative drinking water supplies due to PFAS contamination. But the DOD only provides alternative drinking water when PFAS levels are above 70 parts per trillion, or ppt, an outdated EPA health standard. 

The number of sites where the DOD will have to provide alternative drinking water is expected to increase once proposed EPA standards are finalized.

EPA is finalizing national drinking water standards for six PFAS this year, but the new standards will likely take several years to be implemented.

“For people who have already been drinking water polluted by the DOD for decades, the new drinking water standards come too late,” Hayes said. 

“The DOD has understood the risks posed by PFAS for decades. Sadly, the DOD is only acting now to address PFAS pollution of nearby wells, and only because Congress is forcing the agency to do so,” he said.

Despite the risks posed by the forever chemicals, DOD spending to clean up PFAS contamination and other pollution has fallen to its lowest level in decades. 

PFAS are highly mobile when they enter groundwater and are highly persistent. Very low doses of PFAS have been linked to suppression of the immune system. Studies show exposure to very low levels of PFAS also can increase the risk of cancer, harm fetal development and reduce vaccine effectiveness.