DENVER — Military and civilian authorities are investigating whether any laws were broken in the unexplained discharge of 150,000 gallons of wastewater tainted with toxic chemicals at an Air Force base in Colorado.

The Air Force Office of Special Investigations and the U.S. Environmental Protection Agency are looking into the release of the contaminated wastewater at Peterson Air Force Base in Colorado Springs, officials said Tuesday.

The chemicals flowed into the city's wastewater treatment system but didn't get into its drinking water, officials said.

The discharge was discovered on Oct. 12 and announced six days later.

Air Force officials have scheduled a news conference Wednesday to discuss the incident and other issues surrounding the chemicals, called perfluorinated compounds or PFCs.

PFCs are an ingredient in firefighting foam used at Peterson and other military installations. They have also been used in non-stick cookware coatings and other applications.

PFCs have been linked to prostate, kidney and testicular cancer, along with other illnesses. The Air Force announced in August it would switch to some other type of foam.

Air Force officials haven't said how high the levels of PFCs were in the wastewater released at Peterson.

The Colorado Springs wastewater treatment system isn't set up to remove PFCs, so they were still in the water when it was discharged into Fountain Creek, officials said. State officials said no communities take water directly from the creek downstream from the treatment plant.

The water was in a storage tank used to recirculate the water to a fire training area, officials said. It would have been re-used in firefighting exercises.

The discharge was discovered during a routine tank inspection. Air Force officials said they found no obvious defects in the tank.

The Air Force is also investigating whether Peterson is the source of PFC contamination found in well water in two other nearby communities, the town of Fountain and an unincorporated community called Security-Widefield.