The federal government has stockpiled enough smallpox vaccine for the entire U.S. population, Thompson said, and soon could issue an order to administer it.

"We want to make sure that the state and local health departments are ready to go," he said.

Thompson spoke of bioterrorism concerns following a meeting of the United States-Mexico Border Health Commission in downtown San Diego. The commission was created two years ago to increase cooperation between the two countries on border health issues.

The conference drew top state and federal health officials from both sides, as well as community health leaders from the border region. Participants touched on bioterrorism, but the meetings focused more on air pollution, tuberculosis, diabetes and drug addiction in the border region.

Interviewed at the conference's close, Thompson said his foremost concern is bioterrorists contaminating food. To avert the threat, the health department, which oversees the U.S. Food and Drug Administration, has hired an additional 832 inspectors, many of whom have been assigned to the U.S.-Mexico border, Thompson said. U.S. officials have also asked for Mexico's collaboration in food inspections, he added.

The United States stopped routine smallpox vaccinations in 1972. The last case in the United States was registered in 1949, and the last naturally occurring case in the world was in Somalia in 1977. The highly contagious disease was declared eradicated worldwide in 1980. But fears that bioterrorists could reintroduce the disease has prompted a call for the vaccine.

Thompson said the health department also is concerned about anthrax and has purchased enough antibiotics to treat 20 million people.

California has received about $100 million of a $1.1 billion federal infusion to upgrade public health systems nationwide to prepare for bioterrorism threats. Thompson said his department has requested a 45 percent increase in that appropriation for next year.

With this money, "we are able to go beyond terrorism," he said. "This infrastructure that we're investing in is going to be good for West Nile virus, for any infectious diseases that come into our country."