CASPER, Wyo. — While Wyoming Department of Environmental Quality officials continue to push the U.S. Army Corps of Engineers for answers at two former Atlas missile sites surrounding Cheyenne, neighboring Colorado is in the final stages of cleanup at its three contaminated sites.
The three sites, contaminated by operations conducted in the 1960s, are located in north-central Colorado, near Greeley and Fort Collins. Colorado Department of Public Health and Environment officials say remediation actions at the sites will be completed within a decade.
Contamination at the Colorado sites is much lower than that of Wyoming’s Atlas Missile Site No. 3. The Colorado sites average a contamination level of 3,600 parts per billion trichlorethylene. At Site No. 3 in Wyoming, levels have reached more than 31,000 parts per billion.
“The thing about these sites is none of them pose an immediate threat to nearby residents,” said Susan Newton, project manager at the Colorado Department of Public Health and Environment. “Although the contamination did occur quite a long time ago, the work is happening now.”
The Corps began investigating Missile Site No. 12, the worst of Colorado’s contaminated sites, in 1996. After a lengthy investigation, the corps began injecting the sites with potassium permanganate to clean up the same TCE pollution that can be found in Wyoming.
Remediation at the site has lowered contamination to 400 ppb TCE.
The Corps and state of Colorado have worked together on the sites to continue remediation at the three sites.
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“The movement on these sites has been satisfactory,” Newton said. “I don’t have a sense of any reluctance or foot dragging. If there was an immediate threat, this would have been maybe cleaned up sooner.”
But Wyoming officials have struggled to establish the same level of cooperation. The added complexities caused by the 315-foot-deep plume of TCE in Missile Site No. 3 have created a difficult decision for the Corps in its investigation that began in 2001.
“It’s expensive,” Jane Francis, geological supervisor at Wyoming DEQ, said. “We need to work as a team, put our heads together and use everyone’s intelligence, and I don’t know that that has happened yet. But we’re working on it.”
The plumes in Wyoming are much larger. The plume at Site No. 4 is more than 12 miles long and threatens municipal water wells in Cheyenne.
Francis said one of the major sticking points in the investigation involves the characterization of the large areas of contaminated ground water aquifer.
“The question is, how do you investigate something like that if you put in three wells? You’re only getting information on 30 feet,” Francis said. “You’re trying to get a handle on over 160 feet. One of the key things to figure out is, where is the source.”
She said Wyoming DEQ has suggested the use of injection to clean up the chemical, but that the solution won’t be that simple in Wyoming.
“DEQ has often suggested injection,” she said. “What will probably have to happen in Wyoming is some combination of technologies. They will have to do something to contain the contamination and something at the source area.”
The U.S. Army Corps of Engineers and Wyoming DEQ officials will meet next week to discuss further action on the projects.