The South Area of the Tooele Depot is a storage facility for conventional ammunition, but until recently was home to 43% of the nation's chemical weapons, an area within it known as the Deseret Chemical Depot. The nearly 30 million pounds of aging mustard and nerve agents were stored in 208 igloos at the facility, awaiting disposal, according to international treaties. The Tooele Chemical Agent Disposal Facility incinerator was built near the igloos, and completed in 1994 at a cost of several hundred million dollars. The controversial disposal plant started burning the chemical weapons at the depot in August, 1996. It was built and operated by the EG&G corporation, and was the first of several incinerators the Army proposed to construct at military facilities across the country, wherever chemical weapons were stored. Having completed the destruction of the country's largest stockpile of chemical weapons as mandated by international treaty, Deseret Chemical Depot was formally closed July 2013, and the incinerator was torn down.