Food and Drug Administration officials acknowledged to a House subcommittee yesterday that federal food safety laws may have been broken in rushing a cattle drug to market, one the agency knew could leave cancer-causing residues in meat.

"They admitted to facts of the cases in numerous instances," Rep. Ted Weiss (D-N.Y.) said of the subcommittee hearings yesterday, "and the facts of the circumstances clearly add up to violations of law, and situations in which the FDA itself adopted policies in total contradiction to the law."

"Illegal sales of highly toxic prescription veterinary drugs have gone on for several years and appear to have completely outstripped the capacity of FDA to control them," he said.

Dr. Lester M. Crawford, head of the FDA's Center for Veterinary Medicine, told Weiss' Government Operations subcommittee that he had granted what he called an "emergency exemption" for one cattle drug. The FDA has no authority to grant such an exemption, subcommittee investigators said.

Crawford gave the "exemption" from normal safety checks on a drug because he said cattlemen had no approved drug to combat an outbreak of liver flukes, a serious parasitic ailment.

"It was a special circumstance," Crawford said. "Something had to be done and what was done was the emergency use of albendazole."

Crawford confirmed that his division had received an opinion from the FDA general counsel that the law did not permit such emergency drug use, but that the exemption had already been granted when the opinion was received.

Said Crawford of the notification that the action was illegal: "There will always be disagreements."

But Weiss pointed out that Crawford had officially listed the emergency exemption as an "investigational permit" to test the drug. Drugs being tested cannot be sold, he told Crawford, then asked, "Did the FDA authorize the sponsor [drug company] to charge for albendazole?"

"Yes," Crawford said.

When the drug was pulled off the market earlier this year as being too hazardous, it was being used on as many as a million animals in 17 states under the "emergency exemption."

The disclosure came on the second day of the subcommittee's hearings on the effectiveness of animal-drug regulation, the first such hearings in more than a decade. Weiss said the testimony demonstrated that the FDA is failing to protect the public from harmful contaminants in the food supply.

In the case of albendazole, Weiss said, the agency approved the exemption after eliciting a promise the Smith-Kline Corp. that its use would be carefully controlled and monitored. But last year, an internal FDA report warned that the use of albendazole was "completely out of control," amounting to "a complete abrogation of the agreement with the sponsor."

According to other FDA witnesses, albendazole was removed from the market in January because of mounting evidence of its cancer-causing properties, and almost immediately replaced with a similar product called clorsulon.

But clorsulon was pressed through to approval so hastily that FDA scientists did not get a chance to review safety tests until two weeks after the drug was on the market. Weiss said this was an action outside the law and one of the worst violations to be disclosed at the hearing.

When the tests were reviewed, the scientists reported that they did not concur that the drug should be approved, but had "serious concerns" about it.

Joseph A. Settepani, acting director of the division's quality control staff, said he was dissatisfied with a memo that "explained away" kidney abnormalities in test animals and had "substantial concerns about environmental impacts."

Clorsulon is phytotoxic, meaning that residues passed on through animal manure are capable of killing plant life.

Crawford acknowledged that the FDA accelerated approval of clorsulon, which subcommittee investigators said was an illegal action.

"Our experiences with using albendazole were uncomfortable," Crawford said. But he denied Weiss' suggestion that he sped the drug's approval in order to have a fluke-killing substance on the market when albendazole was banned in January.

Crawford's remarks were contradicted by FDA documents obtained by the subcommittee, including a memo written in September 1984 by Dr. Norman R. Tufts, chief of the division's bioresearch staff. Tufts wrote that the application would be approved, hopefully in time to fill in for albendazole's phase-out. The memo added that the FDA "better not find anything wrong with clorsulon" or "Dr. Crawford would be furious."

Tufts told Weiss yesterday that he believed the remarks were "made in jest."