Rocky Mountain Arsenal

The Rocky Mountain Arsenal was a United States chemical weapons manufacturing center located in the Denver Metropolitan Area in Commerce City, Colorado. The site was completed December 1942, operated by the United States Army throughout the later 20th century and was controversial among local residents until its closure in 1992.

Much of the site is now protected as the Rocky Mountain Arsenal National Wildlife Refuge.

The Arsenal's location was selected due to its relative distance from the coasts (and presumably not likely to be attacked), a sufficient labor force to work at the site, weather that was conducive to outdoor work, and the appropriate soil needed for the project. It was also helpful that the location was close to Stapleton airfield, a major transportation hub.

In 1942, the US Army acquired 19,915 acres (80.59 km²) of land on which to manufacture weapons in support of World War II military activities at a cost of $62,415,000. Additionally, some of this land was used for a prisoner of war camp (for German combatants) and later transferred to the city of Denver as Stapleton Airport expanded. A lateral was built off the High Line Canal to supply water to the Arsenal.

Weapons manufactured at RMA included both conventional and chemical munitions, including white phosphorus (M34 grenade), napalm, mustard gas, lewisite, and chlorine gas. RMA is also one of the few sites that had a stockpile of Sarin gas (aka nerve agent GB), an organophosphorus compound. The manufacture of these weapons continued until 1969. Rocket fuel to support Air Force operations was also manufactured and stored at RMA. Subsequently, through the 1970s until 1985, RMA was used as a demilitarization site to destroy munitions and chemically related items. Coinciding with these activities, from 1946 to 1982, the Army leased RMA facilities to private industries for the production of pesticides. One of the major lessees, Shell Oil Company, along with Julius Hyman and Company and Colorado Fuel and Iron, had manufacturing and processing capabilities on RMA between 1952 and 1982. The military reserved the right to oust these companies and restart chemical weapon production in the event of a national emergency.

...
Wikipedia