US air force backpedals claim it is not responsible for PFAS cleanup in Arizona

<span>PFAS foam gathers at the the Van Etten Creek dam in Oscoda Township, Michigan.</span><span>Photograph: Jake May/AP</span>
PFAS foam gathers at the the Van Etten Creek dam in Oscoda Township, Michigan.Photograph: Jake May/AP

The US air force has backpedaled on a claim that the supreme court’s recent reversal of the Chevron doctrine shields it against regulators’ orders to clean drinking water the military polluted in Tucson, Arizona.

The air force’s bases partially contaminated water supplies for more than 500,000 people with toxic PFAS “forever chemicals” and other dangerous compounds. In a July letter in which it refused to comply with the Environmental Protection Agency’s May orders to address the problem, air force attorneys cited the reversal of Chevron. It claimed “the EPA’s order can not withstand review”.

However, in a 24 October letter, the air force changed its position, and agreed to partially fund treatment plants that will remove the extremely high levels of PFAS contaminating some of Tucson’s water supplies. The change of course follows an August Guardian story on the issue that generated outrage.

Legal observers who reviewed the claim in August highly doubted it would hold up if the military attempted to act on it.

Related: PFAS linked to gut health issues in young adults, new study finds

The new plan agreed upon by the air force, city of Tucson and EPA was “excellent” and would address the PFAS pollution while stipulating that the air force pay its fair share, said David Uhlmann, an assistant administrator with the EPA’s enforcement division.

“This plan provides a long-term solution to address PFAS pollution in the aquifer,” Uhlmann said, noting that it was especially important in the desert west where drinking water supplies are limited.

The supreme court in late June overturned the 40-year-old Chevron doctrine, one of its most important precedents. The decision sharply cut regulators’ power by giving judges the final say in interpreting ambiguous areas of the law during rule-making. Judges previously gave deference to regulatory agency experts on such questions, and the reversal is expected to have a profound impact on the EPA’s ability to protect the public from pollution.

A 10-sq-mile (26 sq km) area around the facilities and Tucson international airport was in the 1980s designated as a Superfund site, an action reserved for the nation’s most polluted areas.

While several air force bases are responsible for trichloroethylene (TCE) – volatile organic compounds – and PFAS contamination, the municipal airport also used PFAS-laden firefighting foam on the site and is responsible for some of the pollution.

Filtration systems put in place in 2014 for TCE and other chemicals are currently removing PFAS, but the systems were not designed to remove PFAS, and the added burden is straining the system. Officials previously shut down a well in 2021 when contaminated water nearly broke through the system, the EPA wrote. Such a breach could leave the entire Arizona city without safe water.

The air force’s refusal to comply with the EPA order was viewed as an early indication of how polluters will wield the ruling to evade responsibility and underscored the stakes.

Legal observers in August said the military was attempting to expand the scope of the Chevron ruling, and it could not be applied to EPA enforcement actions like the Tucson order – it only affects the rule-making process. Moreover, one arm of a presidential administration cannot sue another, so the military cannot sue the EPA.

Uhlmann said he was not sure why the air force made the Chevron claim, but added he did not “think the statements made in the July letter were views shared by senior defense officials or air force leadership”.

“The EPA and DoD take seriously the obligation of the US government to address PFAS contamination and other forms of pollution related to operation of DoD installations,” Uhlmann told the Guardian.

Part of the dispute lay in the level of responsibility for the pollution, and the new agreement will continue an investigation into the percentage for which each party must pay.

In the meantime, the air force has agreed to pay for 50% of past costs, which the city has so far covered. It will also pay 50% of the future capital costs for new plants, as well as operation and maintenance into perpetuity. If the ongoing investigation finds the air force is responsible for a level of the pollution above or below 50%, then the amount it pays will be adjusted.

In its October letter to the EPA, the air force wrote it is making a “firm commitment” to the plan.