Final design is ongoing for the remainder of the support structures, a tricky proposition due to the volume of waste and mix of chemicals. "We have engaged the world's leading experts to resolve technical questions in designing and building the facility," the Bechtel spokeswoman says.

To add to design and cost issues, a June letter written by the U.S. Defense Nuclear Facilities Safety Board alleged a lack of safety controls in place at the vitrification plant and slow resolution of technical concerns. Energy Secretary Steven Chu enlisted an "independent" team of nuclear and safety experts to review concerns about the plant's safety culture. In its assessment, released on Dec. 1, the team found that while there is room for improvement in communication about safety issues, there was "no widespread evidence of a chilled atmosphere adverse to safety and no widespread evidence that DOE and contractor management suppress technical dissent."

DOE, Bechtel and key site subcontractor URS Corp. also have faced ongoing legal challenges from a site safety manager, Walter Tamosaitis, who claims he was removed from his contractor position in 2010 after raising safety concerns related to plant design.

Frank Russo, Bechtel's vit-plant project director, says that despite the independent safety review's conclusions, improvements are necessary and the site "will immediately initiate actions to implement the team's recommendations." These include a Bechtel-sponsored safety "open house" and the launch of a new website—">www.hanfordvitplantsafety.com—for employees, families and the public.

Even with continuing delays, the Washington state Dept. of Ecology, a key vit-plant compliance monitor and critic, appears to be satisfied with its progress.

"The state is working with [DOE] and contractors to resolve the mixing issues and other technical concerns that have been raised recently. But all of the issues we're watching are in the process of being resolved," says Dieter Bohrmann, a department spokesman. "Washington state has a lot to lose from ongoing delays, and it is our goal to keep this project on schedule so that the plant can begin treating waste in 2019."