Health officials have told people living in 24 homes in Oscoda, Michigan, to stop drinking the water from their wells and to stop cooking with it.
The wells in the northeast town tested positive in December for traces of perfluorinated chemicals, or PFCs, which are extremely long-lasting chemicals that accumulate in the body over time.
The U.S. Environmental Protection Agency says the chemicals are toxic to laboratory animals and wildlife, producing "reproductive, developmental, and systemic effects in laboratory tests."
The groundwater contamination was caused by Wurtsmith Air Force Base, which for decades used fire-fighting foams containing PFCs on its property.
Denise Bryan is public health officer for District Health Department No. 2. She says discussions about how to help the residents long-term are just beginning.
"Long-range, switching well water over to municipal waters has been discussed," she says, "but that's a whole process, and a really good question is who's paying for it. The good news is that unlike Flint, where the municipal water was the concern, here our municipal water is available to help."
Oscoda's city water comes from Lake Huron.
Bob Wagner of the Michigan Department of Environmental Quality says the levels of PFCs found in the wells were quite low – 39 parts per trillion was the highest – but there are concerns that levels could go up and affect more people.
He says state law requires the Department of Defense to determine the full extent of the contamination as soon as possible and submit a full remediation plan, including a test well monitoring system. The Air Force is expected to submit a response to the demands before March 23, the day of an open house and community meeting about the contamination.
Wagner says the state has asked the Department of Defense to provide an alternative source of water to all of the affected residents, and speed up the pace at which contaminated groundwater is being treated.
In 2012, the Michigan Department of Community Health, now the Michigan Department of Health and Human Services, advised people not to eat any fish caught in Clark's Marsh due to high levels of PFCs in fish sampled from ponds in the marsh.
The agency also told people to avoid eating non-migratory fish from the lower Au Sable River downstream of Foote Dam due to PFCs found in fish from the river.