In this image provided by the U.S. Air Force, Airman 1st Class Jackson Ligon, left, and Senior Airman Jonathan Marinaccio, 341st Missile Maintenance Squadron technicians, connect a re-entry system to a spacer on an intercontinental ballistic missile during a Simulated Electronic Launch-Minuteman test Sept. 22, 2020, at a launch facility near Malmstrom Air Force Base in Great Falls, Mont. The Air Force says a review of a Montana nuclear missile base where an unusual number of troops have reported being diagnosed with non-Hodgkin's lymphoma has found no immediate risk factors. The same was true at two other bases that could launch ground-based warheads, the service said in a report obtained by the Associated Press. (Senior Airman Daniel Brosam/U.S. Air Force via AP, File)