FOUNTAIN — More than 1,000 people south of Colorado Springs packed a high school Thursday night and buffeted government officials with questions and concerns about an invisible toxic chemical contaminating public water supplies.

Some have turned to a charity distributing up to 16 gallons a week of free bottled water. Some are relying on relatives who live elsewhere to fill up jugs.

“I’m paying for a clean, consumable product, and I’m not getting it. Definitely I’m angry, frustrated,” retired military airman Mike Ditman, 53, said after the forum. “We’ve been drinking this water for 22 years. It could be causing cancer, kidney problems. They don’t really know. Obviously it is a concern. I raised four kids on this water.”

Colorado Department of Public Health and Environment officials repeated recommendations — especially for women and children, because they may be more vulnerable to the perfluorinated chemicals (PFCs) — to switch to other water as a precaution.

“You may or may not be getting your tap water from an area of concern,” CDPHE water-quality official Tyson Ingals told residents. “We have about 60,000 people in the areas of concern. We estimate 10,000 to 15,000 may be receiving water with PFCs above the level of the heath advisory.”

What about schools? residents asked. How long have people here been drinking water tainted with PFCs? What about property values? Should pets be drinking different water? Could organically home-grown vegetables be tainted?

Local utility officials in Widefield, Security and Fountain — all partially dependent on municipal wells drawing from tainted groundwater — assured residents they are intensifying efforts to dilute supplies by mixing in cleaner water piped from Pueblo, 40 miles to the south. A CDPHE preliminary health assessment has found elevated cancer in the area, but officials emphasized no link to PFCs has been established.

PFCs are among a growing array of unregulated contaminants that federal scientists increasingly detect nationwide in city water supplies. The area south of Colorado Springs ranks among the hardest-hit of 63 areas nationwide where PFCs — used in foam widely used to fight petroleum fires and also in food packaging and stain-resistant carpet — have been measured at levels the Environmental Protection Agency deems dangerous.

EPA officials say PFC levels exceeded a health advisory limit in 1 percent of 4,864 public water systems tested nationwide. That means 5 million Americans in 33 states may be drinking PFC-tainted water.

Officials from El Paso County, the CDPHE and the military now are looking more closely at contamination in the Widefield-Security-Fountain area. Of 43 private wells tested recently, county officials have received results from 37 tests, with PFC levels in 26 exceeding the EPA limit, spokeswoman Danielle Oller said.

In Security, all 32 municipal wells are contaminated, and water officials ranked the wells based on levels of contamination. One well where the level was nearly 20 times higher than an EPA health advisory limit has been shut down. Security officials urged voluntary cutbacks in lawn watering to reduce the need to use contaminated groundwater.

Security Water and Sanitation District manager Roy Heald has divided the city into three zones and said about 25 percent of residents live in a zone receiving water from contaminated wells. The residents in two other zones “are supplied water mainly from surface water sources,” Heald said.

“I am very concerned about it and frustrated,” Melanie Sweeney, 33, a mother of two boys in the problem zone said, pointing out her wheelchair-bound father may be particularly vulnerable. “Nobody is taking responsibility for this, and we feel people are trying to cover it up.”

Next week, utility officials plan to begin re-plumbing, installing new pipelines, trying to blend in more water from Pueblo into that zone and other areas.

“That work will take several months but will help us supply surface water to schools, day cares and the general public in that zone,” Heald said. “We are looking into other ways in which we can bring more surface water into our system to be able to stop using groundwater until treatment is available.”

Air Force representatives at the forum, where residents filled an auditorium, adjacent cafeteria and stood in hallways at Mesa Ridge High School, said the Air Force will pay $4.3 million to set up temporary treatment systems — while local utilities address the long-term implications of contaminated groundwater and a possible fix. Military airfields are suspected as a source of PFC contamination, and a broad investigation is planned, with drilling in October at Peterson Air Force Base east of Colorado Springs.

“Our short-term to mid-term solution is to use more surface water, which is not affected by these contaminants. Our mid-term to long-term solution will be to treat the groundwater,” said Heald, who met with Air Force officials and will continue those discussions. Security also has requested financial help from the EPA, CDPHE and elected officials.

“Security Water is a relatively small water district, and the costs of managing this issue is expensive for our customers,” Heald said.

Security residents typically pay about $25 a month for their water.

Widefield officials said they’ll set up a free bottled water distribution station — limiting residents to 10 gallons a week. They’re relying as much as possible on water from Pueblo, although they may draw from contaminated wells to meet peak demands during summer as temperatures rise.

Fountain utility officials planned to notify residents about PFCs in notices mailed along with July water bills. Fountain normally draws from eight municipal wells, all now contaminated with PFCs above the EPA limit, and has shifted to water from Pueblo while contract engineers search for a solution.

Yet Ingals from CDPHE pointed out that these cities “cannot function on surface water alone. … There are groundwater wells that are being pumped. … The wells kick on and off at different intervals. … Because it is not predicable, we cannot tell you that it always is safe.

“People are being exposed. That is a very serious issue. That is why we are here tonight. We are sampling the wells. We are sampling the tap water.”

EPA officials have suggested that the utilities should encourage residents to consider bottled water.

Every five years, the EPA reviews data on up to 30 emerging contaminants detected in water supplies for which federal controls may be warranted. Because PFCs currently are not regulated under any national water quality standard, state and local officials say they are powerless to control them.

But the EPA in May issued a health advisory limit of 70 parts per trillion for PFCs, raised from a previous limit of 400 ppt. PFC contamination of water at levels exceeding 70 ppt is considered harmful, especially for women and children. A recent CDPHE sample south of Peterson Air Force Base east of Colorado Springs detected PFC groundwater contamination at 2000 ppt.

Prolonged exposure to PFCs has been linked to health harm: developmental damage to fetuses during pregnancy, low birth weight, accelerated puberty and distorted bones. The EPA’s advisory also links the chemicals to kidney and testicular cancer, liver tissue damage, impaired production of antibodies and cholesterol changes.

“EPA appreciates the Air Force’s commitment to the community in El Paso County and the steps they are taking to provide water treatment,” an EPA official wrote in a prepared statement to The Denver Post. “We continue to support state and local communities as they determine appropriate actions and next steps in evaluating and addressing water quality concerns. We have not reviewed Colorado Department of Public Health and the Environment’s (CDPHE) preliminary assessment on cancer and birth outcomes.”

Air Force officials said they are helping as “a good neighbor gesture” — not admitting fault.

“The Air Force is committed to protecting human health and the environment. When missions have an adverse impact on communities, our priority is to restore health and safety,” Peterson Air Force Base spokesman Steve Brady said. “The Air Force is committed to open dialogue with regulators, communities and other stakeholders.”

CDPHE experts in February began a preliminary assessment of cancer rates in the area south of Colorado Springs and on June 30 completed a report showing elevated cancer rates. The CDPHE team found lung cancer rates 66 percent higher than expected, bladder cancer up 17 percent and kidney cancer up 34 percent. CDPHE officials emphasized there’s no clear link to PFCs.

“While there is very limited scientific information on the health effects of PFCs, there have been human and laboratory animal studies that suggest a link between exposure to PFCs and low birth weight. Other human and laboratory animal studies show a possible link — but not a cause-and-effect relationship — between levels of PFCs in the blood and kidney cancer and testicular cancer,” CDPHE toxicologist Mike Van Dyke said.

The assessment looked at births from 2010-14 and all cases of 11 types of cancer from 2000-2014 in 21 census tracts covering Security, Widefield and Fountain. CDPHE researchers compared these with birth and cancer data from the rest of El Paso County.

They found no spike in low birth weights in the areas where water is contaminated with PFCs. But there were a higher-than-expected rates of lung, kidney and bladder cancers.

“Of these types of cancer, only kidney cancer has been plausibly linked to PFC exposure in human and laboratory animal studies,” Van Dyke said.

The increases may be explained by higher rates of smoking and obesity in the area. Smoking and obesity, CDPHE officials said, may be factors explaining the increased kidney cancer.