There was no exposure outside the lab and scientists notified CDC officials of the potential problem on Tuesday, Reynolds said.
The possible exposure is under internal investigation and has been reported to Secretary of Health and Human Services Sylvia Burwell, Reynolds said. Additional employees have been notified, but none has required monitoring.
CDC Director Tom Frieden said he's troubled by the report.
"I have directed that there be a full review of every aspect of the incident and that CDC take all necessary measures," he said in a statement.
In June, at least 52 workers at the CDC took antibiotics as a precaution because a lab safety problem was thought to have exposed them to anthrax.
source: huffingtonpost.com By PHILLIP LUCAS