An Iowa Air National Guard official says the agency supports further testing for groundwater contamination at a base in Sioux City. Preliminary results from a U.S. military report show high levels of toxic PFAS chemicals are present and may be spreading offsite.

It’s not yet known how far toxins known as PFAS, or per and polyfluoroalkyl substances, are spreading beyond the Iowa Air National Guard Base in Sioux City. But authors of the report, which was commissioned by the Air National Guard, suspect the toxic chemicals are migrating off site.

According to the report, which was obtained by Iowa Public Radio, there are an estimated 189 private wells within a one mile radius of the base. A leader in the Iowa Guard said he supports more testing to determine any potential community impacts.

“We’re taking every step that we can and not hindering the process to make sure we can identify any problems that exist. And our next steps from here on out are to just make sure that we’ve got the future testing is being accomplished and make sure that any problem areas are identified so they can get resolved,” said Brigadier General Shawn Ford, the Deputy Adjutant General of the Iowa Air National Guard. "We're just as concerned about this issue as everybody else is."

The U.S. Environmental Protection Agency's current health advisory for PFAS in drinking water recommends levels should not exceed 70 parts per trillion. According to the Sioux City report, at one hot spot anaylsts detected levels in the groundwater as high as 8,610 parts per trillion, more than 100 times the EPA's limit.

The federal health advisory is voluntary, and does not carry the force of the law. There are currently no legally enforced limits for PFAS at the federal level, or in Iowa, though other states have initiated widespread testing or set their own regulations.

Researchers have linked exposure to PFAS to a slate of negative health outcomes, including increased risks for certain cancers and immune, fertility and hormone issues.

If any potential contamination in private wells is linked to the base's operations, Ford said the Air Force will support residents, and will work to supply alternative water sources.

“If they find out that there is contamination and the Air Force was a contributor to the contamination, then they will take steps to provide suitable drinking source for those people on the wells,” he said.

Ultimately, it’s up to Air Force officials in Washington to decide if more testing is needed in Sioux City. The finalized report on PFAS contamination at the Sioux City base is expected to be done in April. Similar testing has also been conducted at the Iowa Air National Guard Base in Des Moines.