It may be years behind schedule, but the cleanup of Atlas Missile Site 4 west of Cheyenne is moving along.
Although Wyoming has other abandoned defense sites, Atlas 4 is the big dog as far as contamination goes.
The contaminated plume west of Cheyenne may be the largest of all the missile site legacies — 4 to 12 miles long and up to 3 miles wide in places.
At issue is the carcinogenic solvent trichloroethylene (TCE) that airmen used to scrub the nuclear warhead rockets of their liquid fuel during the 1950s and 1960s.
Huge amounts of TCE, a known carcinogen that also causes liver disease, ran off the launching pads into the ground and ultimately into the aquifer that provides about 30 percent of the city of Cheyenne’s water.
Cheyenne has already experienced contamination in its municipal systems due to TCE.
The Army Corps of Engineers several years ago built a water treatment plant for the city as well as carbon filter systems for area landowners who rely on well water.
Meanwhile the contaminated plume is moving slowly but inexorably toward the city of Cheyenne.
The leading edge is estimated to be about 7 or 8 miles west of the capital city.
Many of the members of the Restoration Advisory Board (RAB) for the Atlas 4 site, a group of local citizens, have been frustrated in recent years because of the lack of progress by the Corps in dealing with the problem.
I attended some of the earliest advisory board meetings, where it appeared that the Corps people in charge of the project were indifferent to the concerns of the citizens. They deflected questions about the success of various remedies. They referred to the funding problem to take care of abandoned defense facilities nationwide and stressed the complicated geology in the area and the absence of an immediate public safety problem.
Wyoming’s Sen. John Barrasso received complaints about the impasse.
It took some arm-bending to get the Corps to step up action on the plume that threatens the capital city, he said recently during a Senate committee hearing.
It paid off. Last August, soil and groundwater samples from a well dug at a flame pit next to Launching Service Building No. 1 at the Atlas site showed the heaviest concentration of TCE found at the site to date.
The groundwater samples showed TCE levels of 240,000 parts per billion.
This compares to the 5 parts per billion that is the TCE level in water considered safe for human consumption by the Environmental Protection Agency.
During a recent meeting of the advisory group, the corps’ project director, Doug Simpleman, announced that an additional $6.4 million had been awarded for more Atlas 4 field work.
The money will be used to answer all the data gaps at the site.
That study starts next month and it will take eight weeks to compile the data. After that the Corps will decide where to drill more wells to better map the plume’s path, from its source at Launching Service Building No. 1 at one end to its leading edge at the other end.
David Croy, a geologist for RMC Consultants, who is working on the project, said the Corps worked hard setting up this program.
“I think they listened intently to the RAB and the stakeholders,” he said.
Simpleman said that when he was asked to take over the Atlas 4 project he understood that locals were not pleased with the way it was going and felt it had stagnated.
He blamed the sluggish pace on the old “stovepipe” management system, where information went from one person to another and was not well coordinated.
As for treatment of the plume, he said there probably will be two remedies: one at the top and one at the bottom.
“But we can’t let that plume pass into the city,” he said.
“We can’t let that happen.”