By SCOTT HIGHAM and KALEY BELVAL

In November 2012, the U.S. Department of Energy asked contract employees at the Hanford plutonium processing plant in Washington state to take an unusual oath.

The DOE wanted them to sign nondisclosure agreements that prevented them from reporting wrongdoing at the nation’s most contaminated nuclear facility without getting approval from an agency supervisor. The agreements also barred them from using any information for financial gain, a possible violation of federal whistleblower laws, which allow employees to collect reward money for reporting wrongdoing.

Donna Busche reluctantly signed the agreement.

“It was a gag order,” said Busche, 51, who served as the manager of environmental and nuclear safety at the Hanford waste treatment facility for a federal contractor until she was fired in February after raising safety concerns. “The message was pretty clear: ‘Don’t say anything to anyone, or else.’ ”

The company that fired Busche, URS, has said her termination was unrelated to her whistleblowing. Busche and another employee testified before Congress in March at a hearing called by Sen. Claire McCaskill (D-Mo.) to examine the handling of whistleblowers at Hanford.

An Energy spokesman denied that the nondisclosure agreements violated federal law.

“The DOE fully complies with the law,” Brendan Daly said. “We not only encourage but require contractors to report waste, fraud and abuse, with no retaliation.”

Lawyers who represent whistleblowers like Busche say they are seeing a rise in the use of overly restrictive nondisclosure agreements, which prevent employees from reporting fraud, even to government investigators. The agreements incorporate language that goes beyond those that had traditionally protected proprietary information, the attorneys said. In recent months, agreements criticized as overly restrictive have surfaced at Kellogg, Brown and Root, one of the nation’s largest defense contractors, andInternational Relief and Development, a nonprofit organization in Arlington County, Va. The nonprofit collected more than $1 billion in tax dollars for war-related projects funded by the U.S. Agency for International Development.

The Securities and Exchange Commission is investigating the agreements at KBR, and the Special Inspector General for Afghanistan Reconstruction is examining the agreements used by IRD. Both companies have denied wrongdoing, and IRD changed the wording of its agreements after they were written about in The Washington Post.

Fear of retaliation for reporting fraud in the workplace is on the rise, according to surveys of federal employees and workers on Wall Street. The U.S. Office of Special Counsel is investigating reports that the Department of Veterans Affairs retaliated against 37 workers who had come forward with allegations of wrongdoing. Some of those employees had tried to report problems with the VA’s medical appointment scheduling system, which is now the subject of a growing national controversy.

The federal government has been encouraging whistleblowers to come forward and trying to protect them since the Civil War, when Congress passed the False Claims Act to punish war profiteers. Under the act, whistleblowers are entitled to collect a percentage of the fraud they uncover. In one of the largest such cases, American banker Bradley Birkenfeld reported secret deposits by U.S. citizens in the Swiss bank UBS. In 2012, he collected a $104 million bounty.

Other famous whistleblowers include Daniel Ellsberg, who leaked the Pentagon’s secret history of the Vietnam War to the New York Times; Karen Silkwood, who reported safety issues at a nuclear facility run by Kerr-McKee and died in a mysterious car crash; and A. Ernest Fitzgerald, an Air Force official during the Nixon administration who blew the whistle on widespread fraud at the Pentagon, including $400 hammers and $600 toilet seats.