Fort McClellan was officially closed in 1999 and is now operated by the Alabama National Guard. For much of its history, Fort McClellan was one of the principal chemical and biological training centers for the Defense Department. The Chemical Defense Training Facility at McClellan was the only facility in the country where live chemical agents were used in training. All military personnel who worked with chemical weapons were required to train in the sealed chamber at this location, where they faced live agents in full protective gear. Over 28,000 personnel have been through the facility. McClellan had other facilities and training programs for the disposal and detection of nuclear, biological, and chemical (NBC) weapons. The post was also a major military police training center. The Fort covers 45,680 acres, much of which is training range that is still in use, administered by the National Guard, and as a support facility for operations at Anniston Army Depot, a major chemical weapons storage site nearby. Chemical weapons and military police training functions have been moved to Fort Leonard Wood in Missouri.