The Department of Defense and the Environmental Protection Agency are investigating if soldiers at military bases all over the country are drinking groundwater contaminated by chemicals used to fight fires.

Air Force Lt. Col. Eric Badger said the Pentagon identified 664 sites where the military used perfluorinated chemicals while training soldiers to fight fires. Many bases have multiple sites at which firefighting training took place that are now being tested to see if groundwater has been contaminated.

Among the sites are Anacostia Naval Station in Washington, D.C. At the Naval Auxiliary Landing Field Fentress in Virginia, the Navy is giving sailors bottled water to drink instead of using groundwater.

The military is beginning the process of testing those sites to gauge the risk of the chemicals to groundwater, Badger said.

"Because we are in the early stages of the cleanup process, we do not have the full scope of the extent of perfluorinated chemicals contamination and the actions the department needs to take to address the risks to human health and the environment," Badger said.

Perfluorinated chemicals are heat, water and oil-resistant compounds used by the military as firefighting foams. According to the EPA, the chemicals do not break down in the environment. Many people have some trace of the chemicals in their bodies.

The chemicals can cause adverse health effects if a person is exposed for a long period of time. Some studies suggest links between the chemicals and cancer. The EPA is still studying what effects the chemicals have on humans.

The EPA did not answer directly when asked if the water was safe to drink at the affected military bases. Badger deferred questions about the quality of the groundwater to the EPA.

The military is no longer using the 664 affected sites for training, but the chemicals will continue to be used for firefighting purposes, Badger said.

In a statement, an EPA spokesperson said the agency is working with many communities to measure the amount of perfluorinated chemicals in drinking water. So far, data shows a very small percentage of water systems have perfluorinated chemicals in the water, but the EPA is still updating its data.

"This is primarily a cleanup issue due to localized releases and needs to be addressed on a case-by-case basis," the spokesperson said.

The issue was discovered after the EPA issued a provisional health advisory in 2009 identifying the dangerous amount of perfluorinated chemicals in water as 400 parts per trillion. The agency is still working to update that standard.

Badger said the military is following the federal law in its cleanup program by reviewing historical documents and collecting samples of soil and groundwater to identify impacted areas.