OSCODA, Mich. — A Pentagon official has told northern Michigan residents four more years of study are necessary to get a handle on toxic chemicals from a former U.S. Air Force base that are polluting drinking water.

Michigan Radio and MLive.com report Air Force Assistant Secretary John Henderson spoke Wednesday in Oscoda. Henderson says officials want to move faster on cleanup but must “get it right the first time.”

The meeting provided updates about dealing with the per- and polyfluoroalkyl substances, known as PFAS.

The toxins are used in various stain- and stick-resistant household products. They’re also a component of firefighting foam used at the former Wurtsmith Air Force Base in Oscoda and other military installations.

State officials and residents are pushing the Air Force to accelerate testing and treatment of polluted groundwater.