FOUNTAIN — U.S. Air Force contractors on Thursday delivered the first of two $400,000 carbon filters designed to strip away two perfluorinated chemicals contaminating city water supply wells.

Fountain ranks among the most-populated sites around the country and in Korea where the granular-activated-carbon filters are being installed as the Air Force investigates perfluorinated chemicals, or PFCs, spreading from bases, including Peterson Air Force Base east of Colorado Springs. PFCs have been linked to health harm — low birth rates, and kidney and testicular cancers — but public health epidemiological work in Colorado hasn’t been done.

A year after revelations of widespread PFC contamination at levels above an Environmental Protection Agency health advisory limit in water south of Colorado Springs, Fountain officials welcomed the help.

“We’re a public water system making sure we meet the regulations, even the health-advisory level. Our community — this is a priority for them. We’re going to deal with this,” Fountain utilities director Curtis Mitchell said, watching as a crane lowered two 19-foot-tall filtration tanks near a public library.

“This is a huge step forward,” he said, “because it will give us access to some of our groundwater again.”

But farmer Susan Gordon and other residents of the Fountain Creek watershed still are raising questions about the human-health impact of exposure through drinking water.

Gordon for years drank contaminated water from domestic wells and recently received results from a workers comp blood test showing a PFC called PFHxS in her blood at more than 100 times normal level. Three family members and some people who work on the farm with her also had elevated perfluorinated chemicals in their blood.

While she’s healthy now, “who knows what it could mean 10 years from now?” Gordon said. “Not just me, but lots of people living in these communities have been exposed.”

“The right thing for the Air Force to do is to identify the source as quickly as possible and do whatever it takes to stop the underground filtration of the contaminants if that is even possible.” she said. “I also think the community has the right to more information.”

Starting in late July, the 500-gallon-per-minute water-filtering systems attached to two of Fountain’s four municipal wells will begin to remove PFCs called PFOS and PFOA.

Fountain shifted city supplies to surface water sources after contamination was detected last year at levels above the EPA limit of 70 parts per trillion. But nearly 80,000 people in Fountain, Security and Widefield, as well as other communities south of Colorado Springs, long have relied on groundwater as a primary source of drinking water.

Water providers in Security have shifted to surface water delivered from a reservoir west of Pueblo along the Arkansas River, and those in Widefield and Stratmoor Hills have put in water-cleaning systems.

The U.S. government does not regulate perfluorinated chemicals, contained in foam used to douse fuel fires and also used to make products resistant to grease, including carpet, cookware, clothing and fast-food wrappers. The same properties that make PFCs useful fighting fires prevent them from breaking down in the environment. They rank among the worst of hundreds of unregulated chemicals that federal scientists are detecting nationwide in drinking water supplies, including hormones, pesticides, antibiotics and antidepressants.

Making and using PFCs isn’t illegal. Some manufacturers voluntarily stopped producing the most problematic “long-chain” PFCs, such as PFOA and PFOS. But shorter-chain PFCs touted as alternatives, including PFHxS, may cause harm, too. Health data is scarce because studies haven’t been done.

Air Force engineers currently are focused on removing PFOA and PFOS.

The latest scientific research, done at the Colorado School of Mines, indicates that standard carbon filters may not be effective removing short-chain PFCs from water.

Air Force officials on Thursday declined to comment on those findings.

“The Air Force uses proven environmental treatment techniques. If a treatment is not effective, we implement other approaches,” Air Force Civil Engineer Center spokesman Mark Kinkade said.

“The EPA has recommended granular activated carbon filtration for PFOS/PFOA treatment, and the Air Force has used GAC systems to successfully treat various contaminants,” Kinkade said. “After installation, we monitor the system to ensure it is reducing PFOS/PFOA levels. And we are working with industry and researchers to identify new technologies to improve our ability to protect human health and the environment.”

It was unclear whether Fountain’s filters would remove PFHxS. Karl Kuching, business development for the Air Force contractor TIGG, said the filters have proved successful removing some of the PFHxS at a site in Washington state.

Removing short-chain PFCs may require more frequent changing of the carbon, which is injected into the tops of tanks in a slurry and, when exhausted, drained out the bottoms, he said. Two tanks are used. When system operators detect a contaminant “breakthrough,” one tank still filters out contaminants while carbon in the first tank is replaced.

Colorado Department of Public Health and Environment officials regard PFOA, PFOS and PFHpA as chemicals of concern but say there’s not enough scientific data on other PFCs, such as PFHxS. CDPHE has discontinued testing of wells to track an underground plume of contaminated groundwater flowing south toward Pueblo. State officials blamed depletion of EPA funds that enabled the well tests.

An Air Force assessment of PFC contamination at Peterson AFB, which was due this month, has not been made available to the public. A senior Department of Defense official who visited Peterson said the Pentagon will spend $2 billion on site cleanups around the country.

The effectiveness of carbon filters removing PFCs from contaminated water depends on how frequently the carbon is changed, Colorado School of Mines environmental engineer Chris Higgins said.

In Fountain, “the state health department is working out specific guidelines for us,” utilities director Mitchell said. “It will depend on how often we have to use it to meet peak demand.”

Water restrictions last summer reduced water use so that surface water sources met most of the demand. The restrictions might be imposed again after Tuesday, Mitchell said, so untreated well water isn’t tapped.