190821-Z-NJ935-0009
A contractor pressure washes the floor of a massive 600-thousand gallon fuel tank, which stands empty with hatches opened, at the 173rd Fighter Wing in Klamath Falls, Oregon, Aug. 21, 2019. Every ten years, storage tanks like this one are emptied, allowing crews to perform maintenance operations including welding, cleaning, and upgrading parts to help ensure safe operation for another decade. (U.S. Air National Guard photo by Master Sgt. Jefferson Thompson)