RMA South Plant before cleanup (U.S. Fish and Wildlife Service)

December 7, 1941: Japan attacks Pearl Harbor, and the United States is catapulted into World War II. As a deterrent to Hitler's chemical weapons, a 27 square mile plot of farmland 10 miles northeast of Denver, Colorado, is purchased by the government for construction of a U.S. chemical weapons facility. By June 1942, construction of the new Rocky Mountain Arsenal is underway. The main road across the Arsenal is aptly named December 7th Avenue.

Today there is little to remind the casual visitor of the 40 year history of the Rocky Mountain Arsenal as a U.S. Army Facility. An unused military guard house stands at the entrance, and there are a few "No Admittance" signs on side roads. Driving along the entry road, one glances across 17,000 acres of grassland, liberally populated with a variety of wildlife including prairie dogs, deer, coyotes, eagles, hawks, burrowing owls, and many others. There is a small Visitor Center at the terminus of the entry road with interpretive displays about the wildlife, ecology, and history of the Arsenal. Tram tours to observe wildlife are given several days a week. Nine miles of hiking trails extend from the Visitor Center, winding around several small lakes. In March 2007, 16 bison from the National Bison Range in Montana were released on the Arsenal, and in May three bison calves were born. After over a century of absence, wild bison have now returned to the Denver plains, albeit in a most unlikely spot.

Wild Bison, Rocky Mountain Arsenal

So what has happened over the past 65 years to cause this metamorphosis? From 1942 until the early 1980's, the Arsenal served several purposes, including the manufacture of nerve gas and rocket propellant by the military, and the production of pesticides by Shell Oil Company. One report labeled the Arsenal "the most contaminated square mile on earth".

Rachel Carson's 1962 best-seller "Silent Spring" signaled a new public attitude about the environment that sparked a series of new laws regulating the disposal and control of hazardous wastes. In the mid-1960's, ground water contamination was discovered just outside the Arsenal, prompting demands to clean up the facility. Initial cleanup efforts began in the next decade. As the cleanup expenses mounted in the 1980's, conflict broke out between the Army, Shell Oil, and the State of Colorado concerning who would shoulder the costs and how the cleanup would be done. In 1987 the Arsenal was placed on the Environmental Protection Agency's Superfund National Priorities List.

A new direction for the Arsenal was suggested when nesting bald eagles were discovered on the site -- an endangered species on a Superfund site! As a consequence of this discovery, an agreement was reached between the stakeholders to jointly remediate the Arsenal with the objective of turning it into a wildlife refuge. Two decades later and almost $2 billion dollars spent so far, most of the Arsenal has now been cleaned up and turned over to the U.S. Fish and Wildlife Service. Despite some pressure by the Sierra Club to delay public access until the remediation is complete in 2011, the Rocky Mountain Arsenal Wildlife Refuge is now open and enjoying increasing popularity. A small portion of the site has been handed over to Commerce City for construction of a new professional soccer stadium. The Army maintains control over parts of the site undergoing final remediation.

The Rocky Mountain Arsenal cleanup may turn out to be a dual success story. It represents an apparently successful reversal of one of the worst environmental episodes of the 20th century. Amazingly, it also represents a step towards reversing one of the most egregious mistakes of the 19th century -- the near extermination of the wild bison.

For more information on the Arsenal see the official website at:

 http://www.fws.gov/rockymountainarsenal/