Oxygen, what the body needs
Senior Airman Nicholas McGinnis, 31st Logistics Readiness Squadron fixed facilities personnel, places a sample of liquid oxygen in a container April 23, 2015, at Aviano Air Base, Italy. Every 90 days, petroleum, oil and lubricants Airmen inspect liquid oxygen tank locks for leaks and test the oxygen's purity. (U.S. Air Force photo/Senior Airman Matthew Lotz)