21.   But the substance that authorities found in the vials the men were carrying turned out to be an anthrax vaccine for animals.

22.   But Western military officials were shaken and wondered whether the U.S. anthrax vaccine was now obsolete, and whether the same was true of other vaccines in development.

23.   Congressional investigators reported Thursday that they cannot determine whether the controversial anthrax vaccine being administered to U.S. military personnel is safe or effective.

24.   Copies of American military documents found there described anthrax vaccines and how the spores could be used as a weapon.

25.   Despite this creditable record, the military is regularly vilified on Internet Web sites for its handling of the anthrax vaccine.

26.   Federal health officials met on Friday with mail workers and postal officials to provide guidance about a controversial anthrax vaccine offered earlier this week.

27.   Federal health officials have also taken aggressive steps to hasten production of the anthrax vaccine, closely working with its sole US maker, Michigan-based BioPort.

28.   Fleischer would not say if the president had been given the anthrax vaccine, which is now available only to members of the military most at risk for exposure.

29.   Grace Piontek, a rural-route carrier in Hamilton Township, said she was worried about the possible side effects of an anthrax vaccine.

30.   Government and private researchers are working on new anthrax vaccines that they hope will be more potent, safer and require only one or two shots.