As many as 75 scientists working in U.S. government laboratories in the southern U.S. city of Atlanta may have been exposed to live anthrax bacteria.
Officials at the U.S. Centers for Disease Control and Prevention said the risk of infection seems very low and that those exposed are being monitored or given antibiotics as a precaution against the deadly bacteria.
The exposure occurred when a high-level biosecurity lab failed to properly inactivate the bacteria samples that were then used at lower-security labs researching new ways to detect the germs in environmental samples.
Workers in three labs who later came into contact with the potentially infectious samples, were not wearing adequate protective gear because they believed the samples had been inactivated.
Anthrax was highlighted as a potential weapon of mass destruction in 2001 when mail laced with the spores was sent to media organizations and the offices of some U.S. senators. Five people died after the bioterrorism incident.