Federal officials, in response, ordered parties responsible for the site to commission a supplemental study of alternative cleanup options. The EPA didn't choose or approve the environmental engineers that conducted the study, but was aware and “comfortable” with the choice of firms, Whitley said.

The supplemental study, completed in December, doesn’t make specific recommendations. But it does estimate the cost to totally remove the waste and haul it to a licensed facility in another state could cost in excess of $400 million. By contrast, capping the waste is estimated to cost about 10 percent as much, or $41 million.

Meanwhile, it concluded that excavating the radiologically contaminated soil and hauling it away posed "the greatest potential risks to the community."

Drey and other critics of the 2008 EPA plan disagree, and question the conclusions of a study paid for by parties who will also have to finance the cleanup. They're concerned the agency is unlikely to change course.

They have long sought for responsibility of the West Lake site to be transferred to the Army Corps of Engineers under a federal program begun in the mid-1970s to cleanup sites tied to the government’s atomic energy and weapons program.