The U.S. Department of Defense has quietly pushed back its timeline for cleaning up toxic “forever chemicals” at military bases in Oregon and Washington by six years, without public notice. The delays affect the Air National Guard base in Portland and Fairchild Air Force Base near Spokane, both among nearly 140 military sites nationwide facing postponed investigations and remediation efforts for perfluoroalkyl and polyfluoroalkyl substances (PFAS). These man-made chemicals, widely used in firefighting foam, nonstick cookware, and waterproof materials, have been linked to cancer, heart disease, high cholesterol, and birth defects.…