Although conducting studies on pathogens is crucial for understanding how they work and how diseases can be effectively treated, researchers who handle disease-causing viruses and bacteria are at risk of possible exposure.

The threat of getting infected while handling pathogens becomes more apparent in the case of scientists at the Centers for Disease Control and Prevention (CDC) who may have been exposed to anthrax bacteria.

On Thursday, the CDC said in a statement that about 75 scientists who work at CDC laboratories in Atlanta are being monitored after possible exposure to live Bacillus anthracis, which causes anthrax.

The agency said that the affected CDC staff may have been exposed to anthrax bacteria after scientists at a high-level biosecurity laboratory failed to observe safety protocols to inactivate the bacteria and then transferred the samples, which may have included live bacteria, to three lower-security CDC laboratories that are ill-equipped for handing live anthrax.

Believing that the bacteria were inactivated, the scientists working in the labs with lower biosafety levels did not wear personal protective equipment when they handled the samples, which were intended for research on detecting dangerous pathogens in environmental samples.

Procedures that were conducted in two of the affected labs between June 6 and June 13 may have also aerosolized the spores. The possible albeit unintentional exposure was first discovered on June 13 after live anthrax bacteria colonies where found in the original bacterial plates that were used by the researchers. The plates were negative for the anthrax bacteria when the samples were sent to other laboratories. The CDC said that environmental sampling and decontamination were already done and the affected laboratories will be reopened once deemed safe to operate.

Although the CDC assessed the risks of infection to be very low, potentially exposed staffs were already provided antibiotics. The agency also said that based on current reviews, it will not be necessary for the other staff, family members and the public to take protective measures as they are not at risk of exposure.

The CDC said that ongoing investigations will determine why the validated protocols were not used and will report findings of the review. Erring staff may also be meted with disciplinary actions.

"Given that CDC expert protocols were not followed, disciplinary action(s) will be taken as necessary," the CDC said in its statement. "In addition, CDC will review the safety protocol again with all employees who work in this area."