Civilian contractors and members of the 28th Civil Engineer Squadron prepare to replace and rewire the alarm system on a JP-8 fuel tank on Ellsworth Air Force Base, S.D., Dec. 28, 2011. These electronic alarm systems are vital to protecting the installation’s fuel supply detecting fires, perimeter intrusions or when the fuel level drastically drops. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)