Two firefighting-foam chemicals – when they find their way into drinking water – pose health risks at much lower levels than the current safety guidelines established by the Environmental Protection Agency, according to a draft federal study released Wednesday.

These chemicals are called per- and polyfluoroalkyl substances or PFAS. They have been found in five Washington drinking-water systems at levels above the EPA guidelines, as well as dozens of private drinking-water wells near firefighting training areas where the foams were used.

Those sites include Fairchild Air Force Base, where disclosures about the chemicals have frustrated well owners and prompted Airway Heights to flush out the municipal tap system last summer. The city recently closed a deal to continue buying clean water from the city of Spokane.

The new study by the Agency for Toxic Substances and Disease Registry will be reviewed by the state Department of Health, which is preparing to test several hundred other drinking-water systems in Washington to help assess the scope of the problem. The state also is considering whether to set its own standards for PFAS contamination in drinking water.

The study establishes “minimal risk levels,” which is the amount a person can be safely exposed to on a daily basis, and intended to assist federal and state officials in setting regulatory standards.

For one of these chemicals, the minimal risk level is seven times lower than the current EPA guideline of 70 parts per trillion. For a second one, the level is 10 times lower, according to a review of the study by the environmental working group.

The study also sets minimum risk levels for two other PFAS chemicals that the EPA has yet to establish guidelines for but that have both been found in drinking water.

“I think the study underscores the urgency for the state to take action on these chemicals. The state needs to test water systems to ensure that residents aren’t drinking unsafe levels, clean up contamination and get rid of the sources of the contamination,” said Ivy Sager-Rosenthal, communications director for Toxic-Free Future, which led a coalition of groups that petitioned the Department of Health to develop drinking-water standards for PFAS chemicals.

Much of the contamination has been linked to firefighting foam used on military bases, including Naval Air Station Whidbey Island and Fairchild.

The Defense Department has paid for alternate sources of water and other assistance when the contamination levels reach or exceed the EPA 70 parts per trillion guidelines. If the study prompts regulators to recommend a lower threshold, this could increase the number of water systems and private wells that would need assistance from the military.

The PFAS chemicals began to be produced in the mid-20th century. In addition to firefighting foams, they are found in many products such as carpets and food wrappers, and now are present in the blood of 98 percent of the U.S. population.

The federal review has been of concern to Trump administration officials.

An unidentified White House aide, in a January email released under the federal Freedom of Information Act to the Union of Concerned Scientists, warned the study could be a “potential public-relations nightmare.” And there was bipartisan concern in Congress that the administration might try to delay or alter the findings.

Spokesman-Review reporter Chad Sokol contributed to this report.