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.

Rim Rock Trail View, Colorado NM

An excellent way to experience the Spring season is to visit Colorado National Monument and hike the Canyon Rim Trail, which offers scenic panoramic views of the canyon and plateau country of Colorado and a variety of colorful blooming plants along the way. The trail, following the cliff's edge of Wedding Canyon, stretches from the monument's Visitor Center on Rim Rock Drive to a scenic overlook at Book Cliffs View. This half-mile long trail provides a great introduction to the geology, animal, and plant life of the monument, and is especially enjoyable early in the morning or in late afternoon. 

A Visitor Center brochure identifies some of the plants found on the trail. These plants include Utah juniper, with its blue berries seen in spring and summer, Pinyon pine, Mormon tea (Ephedra), and dwarf sagebrush. Yucca, with bright white blooms in May, and prickly pear cactus, with yellow or hot pink flowers, are also plentiful. Common wildlife on the trail includes mule deer and birds, such as the bright blue scrub jay, canyon wren, and white-throated swift.  Golden eagles and red-tailed hawks are often seen gliding through the canyons. There are also several types of lizards that live in the monument and are active in spring -- Collared, Sagebrush, and Whiptail.