WASHINGTON - The chairman and ranking Republican on the House Energy and Commerce Committee asked the Government Accountability Office on Thursday to review costs associated with nuclear safety and worker "stand-downs" at Washington's Hanford Waste Treatment Plant and tank farms.

In a letter, Chairman John Dingell, D-Mich., and Rep. Joe Barton, R-Texas, asked the GAO to, among other things, determine whether the costs have been paid by contractors or taxpayers. They also asked whether the costs could have been avoided if the Department of Energy did a better job of managing and overseeing its contractors.

The letter cited three stand-downs since 2003, during which work was halted at the Waste Treatment Plant and the tank farms, where 53 million gallons of highly radioactive waste is held in mostly aged, single-shell underground tanks.

"When these stand-downs occur, it is our understanding that DOE usually picks up the tab for any cost overruns," the letter said. "Poor contractor performance and failure to adhere to nuclear safety and other requirements, however, contributed to these stand-downs/slowdowns. Cost and schedule increases might have been avoided had there been more effective regulation by DOE."

The letter continued: "The committee is assessing whether DOE's contractors should be held financially accountable for the costs of any schedule delays and cost overruns due to their failure to adhere to nuclear safety and other requirements."

The letter was also signed by Rep. Bart Stupak, D-Mich., chairman of the committee's oversight and investigations subcommittee; Rep. John Shimkus of Illinois, the ranking Republican on the subcommittee, and Rep. Jay Inslee, D-Wash., a member of the subcommittee.

The letter specifically cited:

-A 2004 incident in which a stand-down was ordered and work halted after workers were sickened by vapors coming out of tanks holding high-level nuclear waste. A later review concluded tank farm workers were not provided with adequate protections and an industrial hygiene program had problems.

-DOE's decision in 2005 to halt or slow construction at the Waste Treatment Plant after federal regulators concluded the project could not withstand possible earthquake risks. The action resulted in a 26-month delay and drove up costs for the plant between $750 million and $900 million

-A pipeline rupture in 2007 that resulted in the leak of 50 to 100 gallons of high-level nuclear waste. Work was halted and a design review was ordered.

The letter said the GAO review was needed to "better understand the cost implications of work stoppages resulting from inadequate worker safety protections and weaknesses in nuclear safety, design, oversight and management" at the Waste Treatment Plant and the tank farms.