A controversial bill to allow drug manufacturers to export drugs that have not been approved for use in the United States will get what is likely to be its final shot at approval by a Senate subcommittee today.

The bill, sponsored by Sen. Orrin G. Hatch (R-Utah), would not only permit the export of drugs not used in this country but also would allow the sale abroad of drugs banned in the United States if justified by "particular diseases or health conditions in the country of import that do not exist in the United States."

Hatch chairs the Senate Labor and Human Resources Committee, which has tentatively scheduled a vote today on the bill. But Democratic opponents boycotted the last scheduled vote because of unrelated issues that will also come up today. Sen. Howard M. Metzenbaum (D-Ohio) says he will fight the bill on the Senate floor if it is voted out of committee, and Rep. Henry A. Waxman (D-Calif.) has warned it may have trouble in the House.

"The future of the drug export amendments is uncertain," said a Senate Labor committee staffer. "It's doubtful that the Senate will take action on this bill before the end of the session."

The bill had been scheduled for markup in August, but the committee couldn't get a quorum because Democratic senators boycotted the meeting over two separate controversies that were to be considered along with the drug export legislation. Both of the actions -- one over the Civil Rights Act and the other over a nomination to the National Labor Relations Board -- are scheduled for markup today before the drug export bill.

Even if the committee does meet, which is uncertain, the chances of discussing the export bill are doubtful because it's last on the committee agenda, said the Senate staffer.

The drug export measure has not been taken up by the House, although the House energy and commerce subcommittee, chaired by Waxman, held hearings on exporting unapproved drugs in July.

Waxman, who declined to speculate on the bill's chances in the House, voiced his personal objections to the bill.

"I have serious concerns about the legislation," Waxman said in an interview yesterday. "This bill raises the specter of us not caring for people in other nations and the possibility that we would allow other people to be used as guinea pigs using drugs that our own Food and Drug Administration has determined are not fit for use here."

Waxman objects that the bill would allow unapproved drugs to be exported to any country in the world, including Third World nations with no government agencies to assure protection to their citizens.

"I wouldn't want to add any credibility to the propaganda efforts of our opponents around the world by allowing them to say to Third World countries that we're going to dump dangerous drugs on their people."

The FDA and the White House support the intent of the legislation. The law now prohibits the export of any drug that has not been approved by the FDA for domestic use, except for antibiotics. But U.S. manufacturers can sidestep this prohibition by setting up production plants overseas. The bill would permit exports if at least one foreign regulatory authority that is approved by U.S. officials accepts the exported drugs as safe.

The effect of the existing export ban "is rather needlessly to deprive" the United States of "plants, jobs and tax revenues which are channeled to foreign countries," Hatch asserted at a June Senate committee hearing.

One unusual aspect of the debate over this bill is that the International Chemical Workers Union, the largest union representing pharmaceutical and drug workers, voiced its "strong opposition," arguing that "the potential effect on jobs is greatly exaggerated." The union has 5,600 workers at 19 pharmaceutical plants across the country.

"Ordinarily, unions favor legislations that save or protect American jobs," said AFL-CIO spokesman Murray Seeger. "It's unusual for a union to take a position that some say is job-destructive.

But, the union asserted in a letter to Hatch, "the jobs that would be created are outweighed by the tremendous ethical disadvantages of the bill. The idea of the bill is morally repugnant and can do nothing but harm the reputation of the United States in the world community."

Hatch testified that the bill had many pre-export controls, including a requirement that an exported drug must be under continuing FDA review and that it must be approved in at least one other country possessing an adequate review agency.

Critics of the legislation argue, however, that even other countries with an "adequate drug approval authority" provide less protection than the United States.