THE BURNED OVER DISTRICT

Their procedures for handling anthrax have allowed as many as 84 people to be exposed to the disease.

The U.S. Centers for Disease Control and Prevention said the number of lab workers who may have been exposed rose from the 75 people first disclosed on Thursday. As of early Friday, 32 staff were taking the powerful antibiotic ciprofloxacin, or Cipro, and 20 were taking another antibiotic called doxycycline, CDC press officer Benjamin Haynes said in a statement.

In addition, as many as 27 people were getting the anthrax vaccine to prevent infection. No illnesses have been reported, but the agency expects more people to step forward now that news of the anthrax scare is public. The agency did not give reasons why other workers were not taking medication.

The safety breach, which originated in the CDC's bioterror lab, raised new concerns about the way laboratories around the world conduct research into the deadliest known pathogens, from anthrax to Ebola and avian flu. CDC has already faced repeated scrutiny over security lapses and mechanical malfunctions at some of its labs dating back to at least 2007...

According to Meechan, researchers in the CDC's high-security Bioterror Rapid Response and Advanced Technology laboratory realized they had sent live anthrax bacteria, instead of what they thought were harmless samples, to fellow scientists in two lower-security labs at the agency.

The initial safety lapse occurred as scientists in the bioterror lab were trying out a new protocol for inactivating anthrax, using chemicals instead of radiation.

Scientists in the Bioterror Rapid Response unit had been preparing an especially dangerous Ames strain of the bacteria for use at the two lower-security CDC labs, the Biotechnology Core Facility and the Special Bacteriology Reference Laboratory, Meechan said. The strain had been used in a bioterror attack in the United States in 2001.

Those teams were experimenting with methods to more quickly identify anthrax in substances and powders sent to CDC from authorities across the country.

It took them a week just to realize their known samples were still live. We should feel glad that they were not handling Ebola at the time.