Naval Construction Battalion Center (NCBC) in Gulfport, Mississippi conducted an environmental exercise to test its response to a simulated diesel fuel spill. The exercise involved NCBC emergency personnel working cooperatively with City of Gulfport emergency responders to contain the spill, secure the area, and conduct cleanup operations. Representatives from Commander, Navy Region Southeast evaluated the exercise, which is designed to improve organizations' abilities to efficiently respond to real hazardous material incidents through practicing response under realistic conditions. The exercise successfully demonstrated that NCBC and Gulfport emergency personnel can effectively coordinate their response when external support is needed.