A national security expert says he was forced to resign last year because of his vocal opposition to the use of lie detectors at his nuclear weapons lab. 

Alan Zelicoff, formerly a senior scientist at Sandia National Laboratories in New Mexico, last week spoke for the first time about his resignation last July. He quit following disciplinary action against him for public criticism of polygraph testing. The lab denies any link between Zelicoff's departure and his public statements. 

The Department of Energy instituted routine polygraph screening for employees at all nuclear weapons laboratories in 1999 to check for leaks of classified information. Zelicoff headed the many scientists at Sandia who objected to the move. 

He published opinion pieces and cited research that suggested polygraph tests might finger innocent employees rather than catching spies. 

A series of disciplinary actions followed the outbursts, culminating in a week-long suspension from the lab in June 2003, according to internal memos provided by Zelicoff. When he returned, he was barred from working on the disease-surveillance software he had developed (see Nature 411, 228; 2001). The lab claimed there was a commercial conflict of interest, which he denies. 

John German, a spokesman for Sandia, said that while he could not discuss Zelicoff's case, lab employees must follow procedures before speaking publicly on matters of national security. The lab memos refer to failures in this area, as well as to an alleged security infraction. 

Zelicoff insists that he followed necessary procedures and says the charges in the memos are groundless. He spoke out about the affair after becoming frustrated that members of Congress to whom he had complained failed to act. Steven Aftergood, director of the Project on Government Secrecy at the Federation of American Scientists in Washington, is dismayed by Zelicoff's claims: "It tells scientists not to rock the boat."