Bush's order added the Department of Health and Human Services to a list of agencies given contracting authority for national defense purposes. The move allows HHS to offer indemnity to companies that would make, store, transport or distribute vaccines for the pharmaceutical stockpile, said White House spokeswoman Claire Buchan.

When asked whether Bush issued the order to address the current bioterrorism scare over anthrax, Buchan said, "It's broader than any one vaccine."

Bush signed the order on a day when federal officials revealed that anthrax had probably killed two workers from a Washington postal facility that delivers mail to Congress. Two others were hospitalized, and health officials said up to nine other workers at the site have shown symptoms consistent with anthrax.