A December report from the U.S. Air Force Civil Engineer Center found high levels of the contaminants perfluorooctane sulfonate, or PFOS, and perfluorooctanoic acid, or PFOA, in groundwater on and around the old Williams Air Force Base, which is now Phoenix-Mesa Gateway Airport and Arizona State University Polytechnic Campus.
The chemicals are common in carpeting, clothing treatments and a type of firefighting foam that Air Force bases used for decades to put out fires. The U.S. Environmental Protection Agency links these chemicals to cancer and birth defects.
Most of the drinking water in this part of Mesa comes from the Colorado River through the Central Arizona Project canal, but about 5% of the area is served by groundwater from "deep aquifer wells," according to the Air Force report.