PHOENIX — The U.S. Air Force plans to test water in the Phoenix area after finding contamination in a nearby base’s surface and groundwater.

The Air Force started requesting permission Wednesday to test about 45 wells within a mile (1.6 kilometers) surrounding Luke Air Force Base in Glendale, the Arizona Republic reported .

A 2017 site inspection revealed that an elevated level of chemicals found in a firefighting foam had seeped into the base’s water, according to the Air Force. The potentially harmful chemicals — perfluorooctane sulfonate and perfluorooctanoic acid — were located in several areas sampled on the base.

Base spokeswoman Becky Heyse said the base’s water is safe to drink.

The Air Force said it does not know if the water around the base is contaminated or how far toxic substances could have spread.

"There are a lot of unknowns at this point," said Stephanie Short, remedial project manager for the Air Force Civil Engineer Center.

The testing will include sites in Glendale, Goodyear and parts of Maricopa County. Base officials briefed local government officials on Tuesday.

"Our goals are to protect human health, keep residents informed throughout the inspection and ensure safe drinking water," said Brig. Gen. Todd Canterbury, 56th Fighter Wing commander.

The base has largely stopped using the toxic foam, which puts out fires on planes and in hangars, Short said.

Most of the hangars have been equipped with a new type of foam.