Ellsworth first to receive EPA incentives
Contractors at Ellsworth Air Force Base, S.D., pour concrete at a propane air mix plant Sept. 29, 2006, in preparation for the installation of four new tanks, each capable of holding 60,000 gallons of propane. The plant, completed in December 1998, was part of the first contract partnership between Ellsworth and Montana Dakota Utilities and today saves the base more than $1 million annually. (U.S. Air Force photo/Airman 1st Class Kimberly Limrick)