Senior Airman Ray Brown, left, and Tyler Ruano, right, 403rd Logistics Readiness Squadron fuels apprentices, test a sample of liquid oxygen from a LOX portable cart, June 8, 2019 at Keesler Air Force Base, Mississippi. Petroleum, oil and lubricants team members handle, test, store and distribute jet fuel, liquid oxygen and liquid nitrogen to aircraft on the flightline. (U.S. Air Force photo by Tech Sgt. Michael Farrar)