WASHINGTON (AP) - While senators debate shielding childhood vaccine makers from lawsuits, the Bush administration already has provided such protection for at least two vaccines key to the war on terrorism - smallpox and anthrax.

With little fanfare, President Bush used an executive order to immunize smallpox vaccine makers from lawsuits, officials say. Under an order he issued after last year's Sept. 11 terrorist attacks, the Department of Health and Human Services can take on liability for companies it contracts with to fight terrorism.

So far, the department has indemnified two companies providing smallpox vaccine - Wyeth and Aventis Pasteur - and is working on an arrangement with a third contractor, Acambis Baxter, agency spokesman Bill Pierce said Friday. That means that if someone sues for negligence over the vaccine, the department assumes liability rather than the manufacturer.

"We have asked them to do this for us for a program that we are running and managing," Pierce said. "So, therefore, instead of them holding the risk, we're holding the risk, since we are the ones driving this."

The smallpox vaccine hasn't been administered in the United States in years, and the companies are back in the business of providing it only because the government asked, Pierce said. The department isn't taking on liability for the maker of Cipro or other anthrax treatments because those products were already in the marketplace, he said.

Other government agencies involved in national defense have long had the power to indemnify contractors; the Department of Defense, for example, has granted indemnity to Bioport, the maker of an anthrax vaccine. Bush's executive order added the health department to the law allowing it.

While that drew little attention, a move this week to reduce liability for vaccine makers - whether their shots are used to fight terrorism or not - by the GOP-controlled House in legislation creating a Homeland Security Department has brought strong opposition from several Senate Democrats.

They promised Friday to try to take that provision out of the bill, and accused Republicans of providing a last-minute reward to the pharmaceutical industry, a major GOP political donor.

"Does this have anything at all to do with homeland security? The answer is no," said Sen. Byron Dorgan, D-N.D. "This is bad legislation."

They drew support from at least one Republican, Rep. Dan Burton of Indiana, chairman of the House Government Reform Committee. Burton was unaware of the provision when he voted for the measure Wednesday and wants it removed, spokesman Blain Rethmeier said.

"Instead of passing legislation to take away the rights of families with vaccine-injured children, we should be passing legislation to try to help them," Burton said Friday in a written statement.

The Association of Trial Lawyers of America, a major Democratic donor, also was lobbying to have the provision removed.

ATLA spokesman Carlton Carl said it would directly affect parents who believe a child's autism was caused by Thimerosal, a mercury-containing ingredient that used to be a component of several childhood vaccines, Carl said.

The provision would require those who wish to sue former makers of Thimerosal such as Eli Lilly to instead pursue their claims through a federal vaccine compensation program that caps damages at $250,000, Carl said. Medical research has not established a link between autism and Thimerosal, but many parents believe the ingredient may be to blame and are suing manufacturers.

"Ask a parent of an autistic child if $250,000 is going to take care of that child's needs for the rest of his life and you will probably hear that absolutely not," Carl said.

Richard Diamond, a spokesman for retiring House Majority Leader Dick Armey, R-Texas, lead sponsor of the homeland security legislation, said the provision affects pharmaceutical companies beyond those who made Thimerosal and does have national security implications.

Diamond said that under the provision, if an ingredient is listed on a vaccine label, the manufacturer cannot be held liable for something that happens as a consequence of the ingredient. It's up to the physician prescribing the vaccine to weigh the dangers involved, he said.

"We put that in there because if these companies are being sued by trial lawyers, they are going to be reluctant to put lifesaving medicines on the market," Diamond said.

The White House and Republican leaders in the House and Senate supported the provision, which first appeared in a proposal earlier this year by Sen. Bill Frist, R-Tenn., though Frist did not add it to the homeland security legislation, Diamond said.

Diamond declined to say who first sought to have it added to the bill.

"There's a lot of stuff that gets thrown into the mix," Diamond said. "We'll take ultimate responsibility for it."

Eli Lilly spokesman Edward Sagebiel said the company sought the language when Frist first proposed his vaccine legislation, but had not lobbied on it since. The Pharmaceutical Research and Manufacturers of America also supported Frist's bill but did not lobby to have the vaccine provision added to the homeland security bill, spokeswoman Jackie Cottrell said.