Donald Trump’s Immigration and Customs Enforcement (ICE) is planning a detention facility for children and their families on one the nation’s most Pfas-contaminated sites, which also serves as a hub for the president’s deportation program.

The England air force base, now called England Airpark, is a sprawling former military facility in Louisiana where Pfas levels in the groundwater have been found at least 41m parts per trillion (ppt).

Federal drinking water limits for several Pfas compounds range from 4-10 ppt, meaning the levels have been at least 575,000 times higher than the limit. Military bases are often contaminated with high quantities of Pfas, but England’s groundwater has shown the highest levels ever recorded, and it is among the most Pfas-polluted sites in the US.

England is also contaminated with other highly toxic chemicals, like TCE and a range of VOCs, while officials have raised concerns about asbestos in the barracks. Though the base likely draws its drinking water from elsewhere, the chemicals are also in the soil and air, public health advocates say.

That raises a health risk for kids and families staying at the site, added Jared Hayes, a senior policy analyst with the Environmental Working Group non-profit, which tracks military pollution nationwide.

“There shouldn’t be housing at contaminated bases and we need to be cleaning up this stuff much faster if we’re going to put people in harm’s way,” Hayes said.

The US Department of Homeland Security said in a statement: “We have no new detention centers to announce at this time.”

The US Environmental Protection Agency and ICE did not respond to a request for comment. Project officials told the Guardian in March that the lease for the site was being finalized and it could be operational within 60 to 90 days.

Pfas are a class of at least 16,000 compounds typically used to make common products that resist water, stains and heat. They are called “forever chemicals” because they do not naturally break down and accumulate, and are linked to cancer, kidney disease, liver problems, immune disorders, birth defects and other serious health problems.

Pfas are a common ingredient in firefighting foam used at airports and military bases, and the Department of Defense is in the process of phasing it out because the highly toxic substance has widely contaminated water and the environment around more than 770 bases nationwide.

ICE is proposing a children’s detention center for a “first of its kind” short-term facility that officials involved have said would hold migrant families and unaccompanied children next to a runway from which they are flown out of the US. The larger England Airpark complex holds a private Geo Group detention center, which the Guardian previously investigated over a range of abuses.

The project’s developers have said the facility will confine family groups and children for between three and five days inside a converted military barracks, and will only house those who voluntarily choose to “self-deport”. Immigrant rights groups say the “self-deport” claim is misleading, and most are in the program involuntarily. It is also likely they will spend much longer than five days at the centers, advocates say.

The firefighting foam was used in training exercises around the base. It traveled to the groundwater via the soil, meaning the soil is contaminated with the chemicals. The base also held burn pits the military used to incinerate munitions, trash, human waste, toxic waste, plastic and a range of goods and chemicals. Jet fuel is typically used as an accelerants, and the pits are notorious for polluting the immediate region with a range of substances, including Pfas.

The chemicals are highly mobile and volatile, meaning they easily move through the environment, including from the ground into the air. Children are especially at risk to the chemicals’ health effects because their bodies are smaller. The health impacts of exposure at once to all chemicals used at the base remains unclear.

“The risk for people living on site is in the dust and in the air, and we don’t know what levels are in the dust, or if the kids are playing outside – these can be areas of concern,” Hayes said before adding that the military is not testing soil and air at the site.

Frances Kelly, with Louisiana Advocates for Immigrants in Detention, said water is piped in from the nearby city of Alexandria. The city, however, also draws from the groundwater and it is at least publicly unclear where the plume’s edge lies. Records from nearby Pineville show elevated levels of three types of Pfas compounds, though not those that are the main compounds on England Airpark.

Kelly said deed records show the property is restricted to industrial use, and questioned why the site is being used for housing. Industrial land requires stronger cleanup than industrial land.

A spokesperson with the airpark said the Pfas pollution was not on the barrack site, but did not immediately respond to questions about whether it had tested air and soil.

Hayes said federal records do not indicate that Pfas cleanup has begun, and the military remains in its remedial investigation phase. That involves mapping the groundwater plume.

“It doesn’t appear that they’re doing the construction of cleanup, which means they’re doing testing and mapping, so the plume is going to get bigger at the site,” Hayes said.

Though levels of Pfas in the groundwater have dropped in recent years, they still remain astronomically high. Because the military is not actively removing the plume, the lower levels only mean that the plume is spreading out in the aquifer, so Pfas is not as concentrated in around the source of the pollution.

It is unclear whether there is any legal action that can be taken, but advocates are continuing to try to derail the plan.

“There’s always a way to undo it,” Kelly said.