Up to 86 Atlanta-based lab workers at the Centers for Disease Control and Prevention may have been accidentally exposed to anthrax this month due to a safety problem, the agency said Thursday, according to CNN.

Experts say this appears to be the largest incident involving the dangerous bacterium and potential bioterrorism agent in a U.S. lab in 10 years. Although CDC officials say the risk of infection is low, employees are being monitored or given antibiotics that would prevent the onset of symptoms.

''Based on the investigation to date, CDC believes that other CDC staff, family members and the general public are not at risk of exposure and do not need to take any protective action,'' the agency said in a statement, according Boston.com.

As of Thursday afternoon, the agency's Occupational Health Clinic had examined 54 employees identified as having been in the labs or hallways at the time of exposure, according to CDC spokesman Tom Skinner. The CDC says that in addition to taking antibiotics to prevent a possible anthrax infection, 27 staffers were also given the anthrax vaccine.

The scare was caused after a lab inadequately inactivated samples, which were then transported and used for experimentation in three laboratories not equipped to handle anthrax. Believing the samples were inactivated, workers in those labs did not use protective equipment, the CDC said.

The exposure was discovered June 13.

Early symptoms of anthrax can resemble the flu.

"In the worst-case scenarios, literally, within a day or two of exposure, if you've inhaled spores and if they are very lethal, one begins to get -- as they say -- the standard flu symptoms -- high fever, malaise," said Leonard Cole, a bioterrorism expert. "You get lazy. You feel sick. You get headaches. You get bone aches.

"And then after a day or two, in the worst case, if you don't get treatment, it could be lethal for you, and beyond treatment," he said.

The CDC said disciplinary action will be taken.