A significant portion of the stockpile of mustard agent in the United States was stored at the Edgewood Area of Aberdeen Proving Ground in Maryland. Approximately 1,621 tons of mustard agent were stored in one-ton containers on the base under heavy guard. A chemical neutralization plant was built on the proving ground and neutralized the last of this stockpile in February 2005. This stockpile had priority because of the potential for quick reduction of risk to the community. The nearest schools were fitted with overpressurization machinery to protect the students and faculty in the event of a catastrophic explosion and fire at the site. These projects, as well as planning, equipment, and training assistance, were provided to the surrounding community as a part of the Chemical Stockpile Emergency Preparedness Program (CSEPP), a joint program of the Army and the Federal Emergency Management Agency (FEMA). Unexploded shells containing mustard agent and other chemical agents are still present in several test ranges in proximity to schools in the Edgewood area, but the smaller amounts of poison gas () present considerably lower risks. These remnants are being detected and excavated systematically for disposal. The U.S. Army Chemical Materials Agency oversaw disposal of several other chemical weapons stockpiles located across the United States in compliance with international chemical weapons treaties. These include the complete incineration of the chemical weapons stockpiled in Alabama, Arkansas, Indiana, and Oregon. Earlier, this agency had also completed destruction of the chemical weapons stockpile located on Johnston Atoll located south of Hawaii in the Pacific Ocean. The largest mustard agent stockpile, of about 6,196 tons, was stored at the Deseret Chemical Depot in northern Utah. The incineration of this stockpile began in 2006. In May 2011, the last one-ton tank of mustard agent was incinerated at the Deseret Chemical Depot, and the last mustard agent artillery shells at Deseret were incinerated in January 2012.