American Media had said seven employees, including Blanco, tested positive for exposure to anthrax. But Agwunobi said there were only three cases of concern: Stevens, 63, the employee who died, Blanco and fellow mail room worker Stephanie Dailey, who has been receiving antibiotics.
Testing on other employees, Agwunobi said, was inconclusive. All 300 of American Media's employees were scheduled to undergo a second round of blood tests today.
Investigative teams combing the offices of American Media, which publishes many of the country's most popular supermarket tabloids, have found anthrax spores in the mail room and on Stevens' computer keyboard. But FBI officials said the letter that may have infected Stevens and the others was thrown out with the garbage and has been burned.
Many American Media employees expressed fear about returning to their building, which has been quarantined since Oct. 7. The company said Tuesday it would seek alternative office space for the employees' "emotional well-being."
The bacteria was detected on equipment at a post office that handled American Media's mail, U.S. Postal Service officials said. It was disinfected overnight by the Environmental Protection Agency and the facility reopened Tuesday.
Judy Johnson of the Postal Workers Union called on authorities to warn seven other companies in the Boca Raton area that their mail might have been tainted with anthrax because they shared mail-sorting slots with American Media.
Florida Gov. Jeb Bush, the president's brother, warned residents that false anthrax alerts could lead to 15 years in prison. "If people are caught, they are going to be prosecuted," Bush said, "and if they are prosecuted, they are going to serve long prison sentences."
Contributing to this report were Times staff writers James Gerstenzang and Marisa Schultz in Washington, John J. Goldman and Elizabeth Jensen in New York, John-Thor Dahlburg in Miami, Marjorie Miller in London, David Holley in Warsaw, researcher Anna M. Virtue in Miami and special correspondent Iva Drapalova in Prague.