Anthrax Scare Is Latest CDC Lab Security Lapse

— -- An anthrax scare is the latest in a string of safety and security lapses at the U.S. Centers for Disease Control and Prevention, the federal agency charged with preventing the spread of infectious diseases.

Roughly 84 workers at CDC’s Atlanta headquarters may have been exposed to the deadly bacterium, Bacillus anthracis, after a breach at the agency’s Bioterrorism Rapid Response and Advanced Technology Laboratory, the agency confirmed today. The number of workers being monitored for anthrax was revised from 75 when the lab breach was announced Thursday.

“We are devastated. It is unacceptable. This is what we do best,” Paul Mecham of CDC’s Environment Health and Safety Compliance Office told ABC News. “Our people are our number one resource. We are going to find out what went wrong and we are going to fix it.”

CDC Workers Potentially Exposed to Anthrax-Causing Bacteria

Air Leak Sparks Safety Fears at CDC

Were the 2001 Anthrax Attacks Preventable?

At least three different incidents between 2007 and 2012 also called into question the CDC’s laboratory safety and security systems, which are designed to keep dangerous pathogens like smallpox, monkey pox and SARS from escaping into the general population.

No illnesses were reported in connection with the incidents, all three of which involved malfunctioning airflow and ventilation systems.

The possession, use and transfer of dangerous biological select agents and toxins, including Bacillus anthracis, are overseen by the Federal Select Agent Program, which is operated by CDC in conjunction with agents from the U.S. Department of Agriculture.

The program, which essentially allows CDC to conduct self-inspections, was called into question in 2008, when a door to a CDC lab housing Coxiella Burnetii was found to be sealed with duct tape after a ventilation system malfunction.

"Laboratory safety is not an area where you want to have this much self-policing," said ABC News’ chief health and medical editor Dr. Richard Besser, who ran the part of CDC that included the Select Agent Program between 2005 and 2009. "There is clearly an appearance of conflict of interest in having the inspection program at CDC given the number of laboratories housed within the agency. This has been a long-standing problem.”

Calls to the CDC regarding their laboratory safety procedures and oversight were not immediately returned.

The 84 workers involved in the anthrax scare have been offered antibiotics and vaccination, CDC officials said, adding that at least 54 of the workers have been examined and 27 have been vaccinated. So far none have shown signs of illness, but symptoms can take two months to appear, according to the agency,

Left untreated, the inhaled form of anthrax can be deadly in 85 percent of cases, according to the CDC. Even with treatment the fatality rate is as high as 45 percent.

Anthrax is not contagious and the general public is not at risk, CDC officials said.

ABC News' Dr. Richard Besser and Linzie Janis contributed to this story.