Senior Airman Steven McCarthy, 22nd Logistics Readiness Squadron Petroleum, Oils and Lubricants flight fuels laboratory technician, examines a jar of fuel for visual contamination, July 14, 2015, at McConnell Air Force Base, Kan. Visual inspection is one of the first steps in the process to check fuel for particular contamination, which can cause serious mechanical problems on aircraft if left untreated. (U.S. Air Force photo by Senior Airman Victor J. Caputo)