The Department of Energy's former security director told a House panel yesterday that his superiors forced him out of his job two months ago in retaliation for his repeated warnings that security was failing at the nation's nuclear weapons laboratories.

Edward J. McCallum, a retired Army lieutenant colonel who headed DOE's Office of Safeguards and Security, said the department has a "long history of suppression and reprisal" against employees who disclose security breaches.

The House Committee on Government Reform invited testimony from McCallum and three other "whistleblowers" at the departments of Energy and Defense who said their careers suffered after they warned about arms sales, technology transfers or espionage involving China.

McCallum's supporters on the committee said they were appalled that he lost his job just as the Energy Department began to acknowledge the legitimacy of his concerns about the alleged theft of secrets from DOE's nuclear weapons laboratories.

"I think the record will show that nobody has fought harder to try to improve security at DOE labs than Colonel McCallum," said the committee's chairman, Rep. Dan Burton (R-Ind.).

Rep. Henry A. Waxman (Calif.), the committee's ranking Democrat, added that he too is "particularly troubled by the treatment Mr. McCallum has received."

McCallum was placed on administrative leave with pay in April -- three days after he was asked to testify before the President's Foreign Intelligence Advisory Board on security lapses at the labs -- for what Energy Secretary Bill Richardson has described as a "serious security infraction" involving classified information.

The alleged infraction took place in telephone conversations between McCallum and Jeff Peters, a security official who had lost his job at Rocky Flats, a heavily polluted nuclear weapons facility in Colorado. Peters tape-recorded the conversations, in which he and McCallum discussed a variety of security breaches.

Transcripts of the phone calls were posted on the Internet in early April by attorneys representing another Rocky Flats security official contesting his dismissal. McCallum denied that anything he told Peters was classified.

Also testifying yesterday were:

Jonathan D. Fox, an attorney at the Defense Special Weapons Agency, who said he was forced by Pentagon superiors to rewrite a 1997 memorandum to change his conclusion that China was a nuclear arms "proliferator" to one in which China was deemed a "nonproliferator." The change was necessary, Burton said, so China could be certified as a nonproliferator at a summit between President Clinton and Chinese President Jiang Zemin.

Peter M. Leitner, an export licensing officer at the Defense Technology Security Administration, who said he has been subjected to "one adverse harassing act after another" since he appeared last summer before a House committee probing technology transfers to China and Chinese espionage.

F. Michael Maloof, an opponent of liberal technology transfers to China at the Defense Threat Reduction Agency, who said he has been "isolated, ignored and subject to political retribution" for refusing to temper his belief that the Chinese military poses a significant security threat to the United States.