By SUSAN MONTOYA BRYAN Associated Press

ALBUQUERQUE, N.M. (AP) — New Mexico's top prosecutor is demanding that the U.S. Air Force close a publicly accessible lake at Holloman Air Force Base, saying Thursday the concentration of hazardous chemicals at the site poses a risk to public health and the environment.

In a letter obtained by The Associated Press, Attorney General Hector Balderas told Air Force officials that sampling shows the contamination — linked to chemicals known as per- and polyfluoroalkyl substances, or PFAS — are dozens of times higher than federal health advisory levels.

In the case of perfluorooctanoic acid, or PFOA, the samples showed 84 times more than the advisory levels set by the U.S. Environmental Protection Agency.

"These sampling results exacerbate the state's concern for its citizens and the environment," Balderas wrote, noting that the presence of the chemicals "poses an ongoing severe threat to members of the public."

Fed by treated wastewater from the air base, the lake already is off limits to swimming. State health officials on Thursday again warned that people should not swim in or drink from the lake. If people come in contact with the water or foam near the shoreline, they should rinse off.

Health officials also warned pet owners to avoid letting their animals drink or come into contact with the water or foam.

New Mexico is preparing to sue the Air Force over groundwater contamination at two bases, arguing that the federal government has a responsibility to clean up plumes of toxic chemicals left behind by past military firefighting activities.

Similar contamination has been found at dozens of military sites across the nation, and growing evidence that exposure can be dangerous has prompted the EPA to consider setting a maximum level for the chemicals in drinking water nationwide. Currently only non-enforceable drinking water health advisories are in place.

New Mexico environmental regulators first issued a notice of violation to the Air Force in 2018 for failing to properly address the contamination at Cannon Air Force Base near Clovis. They followed earlier this year on Holloman, saying that base had violated its state permit and had yet to respond to concerns about the pollution near Alamogordo.

Balderas set a deadline of May 16 for the Air Force to respond to his latest request.

The Air Force has repeatedly declined to comment on the state's pending litigation but argues that its response to PFAS contamination in New Mexico and elsewhere has been aggressive.

The military has provided alternate water sources for those in areas where Air Force activity likely contributed to contamination. Officials also have said they've been working with regulators to identify and implement long-term solutions to prevent exposure.

According to a report from independent federal investigators, the U.S. military as of 2017 had spent about $200 million on environmental investigations and other responses related to chemicals at 263 installations around the country. The U.S. Department of Defense has said it could take years to determine a total price tag for PFAS contamination at military sites.

The attorney general's office also is asking that the Air Force make publicly available all information it has related to the risk of PFAS exposure at and around the Holloman and Cannon bases.

Balderas wrote that his requests won't diminish the contamination emanating from the bases, but it will help protect citizens from one pathway of exposure.

Holloman borders Alamogordo, where 31,000 residents rely on groundwater within the Tularosa Basin. Base officials there identified five known sites where the chemicals were released.

The lake is near the popular tourist destination of White Sands National Monument. Some visitors to the area have used the lake's shoreline as a camping spot.

