The U.S. Centers for Disease Control said a laboratory technician may have been accidentally exposed to the Ebola virus.
The exposure occurred earlier this week at the agency's Atlanta, Georgia, headquarters. A CDC spokesperson said a small amount of a live Ebola virus may have been mistakenly transferred from one laboratory to another that was not equipped to handle it.
The technician is being monitored for a 21-day period, the typical incubation period for the disease. The CDC is also determining whether several other workers who entered the lab may also have been exposed to the virus.
The CDC said the technician's risk of exposure to Ebola, even if the virus were active, was believed to be low and that the worker was not being quarantined while under observation.
The spokesperson said the Ebola samples were properly contained within the CDC campus, and there is no risk to the public.
Dr. Thomas Frieden, the head of the CDC, issued a statement calling the incident "troubling," and said he has ordered a full review.
This week's incident follows two high-profile cases earlier this year of mishandled samples of anthrax and avian influenza at the CDC that called into question safety practices at the research institute and drew criticism from Capitol Hill.
An investigation discovered lax oversight of lab workers to follow safety protocols.
Some material for this report came from Reuters.