The city of Westfield, Massachusetts, now has three of its wells off-line.
Westfield shut down two of its wells a few years ago after they were found to be contaminated with chemical compounds the EPA considers hazardous.
The city said the source is firefighting foam used at the Barnes Air National Guard Base.
Westfield has now taken a third well off-line after the state Department of Environmental Protection said it was updating which substances would be included in determining what's safe.
Brian Sullivan is the mayor of Westfield.
"They've added a couple of other fluorocarbons to the levels,and the combination of the five will put us a little bit over the 70 parts per trillion in well two, so we took it off-line," he said.
The city is suing three manufacturers of the foam to try to recover money it will spend to address the problem.
Sullivan said Westfield is also planning to sue the federal government.
