A firefighter from Nebraska’s Army National Guard takes a breather after extinguishing a mock aircraft fire during a qualification training exercise at Ellsworth Air Force Base, S.D., June 20, 2019. Ellsworth AFB is home to one of the last few jet-fueled fire pits in the country. Generally fire pits use propane, rather than jet fuel. Jet fuel fires provide firemen with a more realistic training experience. (U.S. Air Force photo by Airman 1st Class Christina Bennett)