The head of the Occupational Safety and Health Administration and a top agency official contradicted each other yesterday in sworn testimony about the attempted firing of an OSHA expert on cancer-causing chemicals.

The conflict erupted during a tumultuous, three-hour hearing during which Rep. Albert Gore Jr. (D-Tenn.) threatened to summon the House sergeant-at-arms to force OSHA chief Thorne G. Auchter to leave the witness table before the agency official, Dr. Bailus Walker, gave his version of the dismissal of Dr. Peter F. Infante.

After Auchter and an assistant moved back to spectator seats, Walker testified that Auchter had insisted that he send a letter to Infante, notifying him that he would be fired for alleged insubordination, rather than cautioning him informally.

As a member of the Senior Executive Service, Walker told Gore's House Science and Technology investigations subcommittee, "I had to respect the right of the assistant secretary," Auchter, to rule that Infante be notified formally, a procedure that permits appeal.

Auchter initially declined to testify about his role, citing a Wednesday letter from Labor Department Solicitor T. Timothy Ryan Jr. saying that it would be "inadvisable" because Auchter would be judging Infante's first appeal.

But Auchter changed his mind after he and Deputy Solicitor Donald J. Rosenthal considered a letter from House attorneys upholding the right of the subcommittee to investigate the matter.

"Did you direct the firing of Dr. Peter Infante?" Gore asked.

"Absolutely not," replied Auchter, who came to OSHA four months ago.

Warned that this conflicted with Walker's sworn testimony, Auchter said, "I am aware of that."

Was Walker lying?

"I sure hope not," Auchter responded.

Was it on his advice that OSHA proposed to fire Infante, who has headed the OSHA'S Office of Carcinogen Indentification and Classification for 3 1/2 years and has a GS-15 rating?

"No, sir," Auchter answered.

That reply was in direct conflict with Walker's testimony, Gore said.

Auchter contradicted Walker again when he told Rep. Bob Shamansky (D-Ohio) that he had asked Walker, "Are you convinced Dr. Infante should leave the agency?" and got the response, "'Yes, I am.'"

Auchter's conduct was vigorously defended by Rep. Robert S. Walker (R-Pa.), who denounced Gore for leading a "witch hunt." In turn, Gore and Shamansky said they were investigating a cover-up by "political hatchetmen" and a threat to the integrity of all government scientists.

Gore charged that the Formaldehyde Institute, which had complained to OSHA, "wanted this guy [Infante] out of the government, and the only charge they could come up with is that he used OSHA stationery."

The letter Bailus Walker signed accuses Infante of having misrepresented OSHA's position on data on the carcinogenic potential of formaldehyde, a chemical to which some 750,000 workers are exposed. Yet Walker testified that he personally agrees with Infante that the data show formaldehyde to be a carcinogen in animals and a cancer risk in humans. That same view was taken in Tuesday testimony by the director of the National Cancer Institute and three other top federal toxicology experts.

Auchter admitted that no OSHA scientist supported his rejection of the data, and also that Infante had not been told that Auchter had reversed the agency's original endorsement of the data.