Although all land to be included in the Rocky Mountain Arsenal National Wildlife Refuge has been turned over to the Department of the Interior, management of the refuge remains the responsibility of both the USFWS and the U.S. Army. Because some land may still contain chemical weapons devices (such as unexploded projectiles or buried equipment) and cannot safely be integrated into the wildlife refuge, the Fish & Wildlife Service manages only of land. The remainder of the property () is managed by the U.S. Army. The USFWS and Army signed an inter-agency agreement to cooperate in the management of the Army land according to UWFWS principles.