The drinking water for another community near Shaw Air Force Base tested positive for industrial chemicals, expanding the scope of the contamination near one of South Carolina's largest military installations.

Lab results released Thursday show the drinking water at the American Mobile Home Plaza, located directly next to the air base in Sumter County, contains compounds known as perfluoroalkyl and polyfluoroalkyl subtances — PFAS for short.

The chemicals are not regulated by the state or federal governments, but scientists continue to study them for potential links to high cholesterol, ulcerative colitis, thyroid disease, development issues, immunological problems, pregnancy-induced hypertension and kidney and testicular cancers.

The water wells at American are the second public drinking water source known to be polluted with the man-made chemicals.

Testing paid for by The Post and Courier found traces of the same chemicals in the tap water at the neighboring Crescent Mobile Home Park earlier this month.

Those independent lab results prompted the state Department of Health and Environmental Control to collect its own samples at communities surrounding the air base.

The latest results show that American's six drinking water wells have even higher levels of PFAS than the water samples collected at Crescent.

Several of the wells contained chemical concentrations of above 200 parts per trillion. That's far higher than 70 parts per trillion, which the U.S. Environmental Protection Agency established as a recommended health advisory for drinking water.

Laura Renwick, a spokeswoman for DHEC, said the state was handing out carbon filtration systems that can be hooked up to people's faucets. Those devices, DHEC said, should pull out portions of the compounds for several months while state and Air Force officials search for a new source of drinking water for the community.

The main concern with PFAS is long-term exposure to the chemicals, which is why the EPA set a lifetime health advisory of 70 parts per trillion. The compounds are known to build up in people's bodies over time. Toxicologists and medical researchers are most concerned about pregnant women and infants consuming the contaminated water.

Together, the two polluted drinking water systems serve roughly 432 people living just outside the city of Sumter. Both of the mobile home parks are feet away from Shaw's fence line, located just across U.S. Highway 378.

The chemicals that infiltrated the water wells are closely associated with an industrial firefighting foam the Air Force used for decades during accidents and training exercises.

The firefighting product was showered over air bases and was allowed to seep into the soil and down into the groundwater.

The Department of Defense estimates the chemicals could be a concern at nearly 400 Army, Navy, Marine Corps and Air Force bases around the globe.

An Air Force study finalized last year confirmed high concentrations of PFAS were under several locations at Shaw. The report noted some of the contaminated groundwater was less than a mile from the wells used by Crescent and other communities to the south of the base.

The Air Force told The Post and Courier last week it believed its use of the firefighting foam was a "likely contributor" to the drinking water contamination found near Shaw.

The compounds were also found under four other military bases in South Carolina, including Charleston Air Force Base, the former Myrtle Beach Air Force Base, the North Auxiliary Airfield in Orangeburg County and the McEntire Joint National Guard Base.

None of the other bases have been associated with drinking water contamination at this point.