Airman 1st Class Joshua Tabasa, a heavy equipment operator assigned to the 28th Civil Engineer Squadron, tests the air within a confined space to ensure the air is breathable on Ellsworth Air Force, S.D., May 18, 2021. Ensuring the air levels are safe is imperative when conducting a confined space entry to ensure no one is harmed. (U.S. Air Force photo by Airman 1st Class Jonah Fronk)