ELLSWORTH AIR FORCE BASE, S.D. -- The 28th Civil Engineer Squadron conducted a confined space entry to perform work on the base storm drain system's physical security on Ellsworth Air Force Base, S.D., May 18, 2020. Members from the 28th CES were lowered into the space to weld a grate to the walls. Safety was a top priority, and the Airmen ensured proper air levels were met and the proper equipment was used.