Increasing contamination of groundwater around Tucson International Airport is prompting the city to indefinitely suspend use of a treatment plant that draws from wells in the area, officials announced Tuesday.

Though Tucson plans to shut down the plant on June 21, “the utility assures the public the water coming out of the ... plant has been and continues to be safe,” a city statement said.

The contamination is linked to a class of chemicals known as PFAS and found at numerous military sites across the U.S. Growing evidence that exposure to the chemicals is dangerous has prompted the EPA to consider setting a maximum level for PFAS in drinking water nationwide.

An Air National Guard installation is near Tucson International.

Contaminants have been below detection limits, but "the rising levels would create the risk of PFAS entering the drinking water system if operations were to continue without further measures in place," the statement said.

Customers served by the plant will instead receive water from other sources, the statement said.

The plant's original purpose was to remove industrial contamination.