A nuclear engineer who was fired by his contractor employer in 2013 after he warned of waste disposal safety risks at the Hanford, Wash., nuclear site agreed to accept a $4.1 million settlement.

Walter Tamosaitis, according to an Associated Press report on Wednesday, settled with his former employer, San Francisco-based subcontractor URS Inc. (now AECOM), which had removed him from his post as a manager at Hanford’s Waste Treatment Plant in 2010. He and colleague Donna Busche, the former manager of environmental and nuclear safety for URS, questioned the company’s long-term process for containing radioactive leaks from World War II-era legacy storage tanks and creating a new process for converting them to glass for safe and permanent storage.

Both had testified on Capitol Hill on the rights of whistleblowers as the matter went through the courts, and Tamosaitis had been awaiting a trial next year.

Tamosaitis said he was told as early as 2006 by his URS managers not to raise safety concerns about proper handling of plutonium. “Those issues stood in the way of Bechtel [the prime contractor] winning their award,” he said. “Whether the project is going forward, backward, or standing still, they’re going to get their funds.” He was fired only weeks after Energy Secretary Ernest Moniz released a staffwide memo calling for a culture that encourages honest whistleblowers. And, Tamosaitis added, URS withheld his severance pay until he agreed to sign a statement granting them immunity, a move he likened to “extortion.”

AECOM said it reached the settlement to avoid the cost of litigation. “The company strongly disagrees that it retaliated against him in any manner,” the company said in a press release. “The company has not tolerated, and will not tolerate, retaliation or harassment in any form against anyone who raises a safety issue in good faith.”

“We are very pleased that Walter can get on with his life after five years of litigation, and that he has been vindicated,” said his attorney, Jack Sheridan. “This settlement sends a message to whistleblowers everywhere that integrity and truth are worth fighting for, and that you can win if you don’t give up.”