The Senate yesterday unanimously approved a $5.6 billion, 10-year program to speed development and stockpiling of vaccines, antidotes and other medical measures to help protect the United States from the consequences of a bioterrorist attack.

The House approved a similar "Project BioShield" bill last year and plans to accept minor changes made by the Senate, putting the legislation on track for final passage later this week or in early June, House leadership aides said.

Although Congress has approved other bioterrorism initiatives, none is as ambitious in its investment in countermeasures to protect the nation from a threat that lawmakers have experienced in the form of letters to their offices that were laced with anthrax and ricin.

The legislation, approved 99 to 0, provides $5.6 billion over the next decade, including $885 million appropriated for this year, for purchase and stockpiling of new vaccines, medicines and diagnostic devices for which a commercial market does not now exist.

The government will guarantee purchase of these products, providing an incentive for private companies to invest the capital needed to develop them.

Among the threats covered by the bill are anthrax, smallpox, botulism, plague and Ebola virus, along with radiation generated by a nuclear device or "dirty bomb."

The bill also seeks to streamline and speed research on defenses against bioterrorism by giving the National Institutes of Health new flexibility in funding its projects, including expedited peer reviews in awarding of grants and faster hiring of technical experts. and greater latitude in procurement of supplies.

In the case of a health emergency, it would allow the government to use vaccines, treatments and products that have not been approved by the Food and Drug Administration. Patients would have to be informed that no government approval has been given, along with potential risks and benefits. Patients would have the right to refuse treatment.

The legislation -- proposed by President Bush in his 2003 State of the Union address -- is needed because the country is "less than adequately prepared" to protect itself from bioterrorist attack, Majority Leader Bill Frist (R-Tenn.) told the Senate as it prepared to vote.

Frist recalled that letters containing anthrax spores were received in congressional offices in 2001 and that ricin, a deadly poison, turned up in the mailroom of his office this February. "Bioterror is here. It's on our own soil, hit this nation, hit this Capitol, hit the entire East Coast, and indeed it was deadly," he said.

In a measure of the strong bipartisan support for the bill, Sen. Edward M. Kennedy (D-Mass.), who worked with Frist and Judd Gregg (R-N.H.) in drafting the legislation, described the bill as "a major step toward giving the nation's health care professionals the support they need to respond to attacks with biological, chemical or nuclear weapons." But he said it must be followed by more funding for hospitals, health agencies and homeland security.

Senate passage of the measure was greeted enthusiastically by the biomedical industry. "Project BioShield is a critical first step toward the development of the drugs and vaccines needed to protect our nation's citizens and military personnel," said Carl B. Feldbaum, president of the Biotechnology Industry Organization.

The Senate vote ignited a minor rally in the shares of companies seen as likely to benefit from the bill. Some of these companies have been working since shortly after the Sept. 11, 2001, terrorist attacks to develop defenses against biological agents and radiation, but they have struggled to convince investors there is likely to be a sustained market for the products. The Senate's action made that seem more likely. For instance, shares of Hollis-Eden Pharmaceuticals Inc. rose 32 percent to close at $10.40 in heavy trading yesterday. The San Diego firm is testing a radiation drug that it hopes to sell to the government under Project BioShield.

Sen. Edward M. Kennedy (D-Mass.) speaks at a news conference accompanied by Health and Human Services Secretary Tommy G. Thompson, left, and Senate Majority Leader Bill Frist (R-Tenn.).