A USDA investigation has revealed more mistakes behind a June incident that saw over 75 Center for Disease Control staff exposed to live anthrax. A summary of the results, published today ahead of a House Energy and Commerce Committee meeting, elaborates on a similar report by the CDC, which found that one of its facilities failed to sterilize samples before sending them to a lower-security lab. In today's meeting, the Subcommittee on Oversight and Investigations will attempt to determine whether this and other security breaches were an established pattern at the CDC, and whether Congress or the USDA should take further action to make sure they don't happen again.

According to this and previous reports, in early June, researchers at its Bioterrorism Rapid Response and Advanced Technology facility attempted to sterilize samples so that they could be safely studied in lower-security conditions. But the lab lacked a standard operating procedure and declared the samples safe prematurely. The new report also found a worrying lack of security both before and after the contamination was discovered.

"Anthrax was stored in unlocked refrigerators in an unrestricted hallway, and workers freely passed through the area at the time of inspection. Signs were not even placed on the refrigerators to prevent their being opened. Where a sign did note use of inactive anthrax, it did not prohibit entry. The key to one of the refrigerator doors sat in its lock. At the time of inspection, containers of anthrax were missing and had to be tracked and located by the inspection team. Anthrax still was sitting in an unregistered and unlocked lab and other areas that had not been registered for special agent use or storage."

"Researchers could not remember if they used expired bleach."

The USDA also criticized the CDC's equipment. "Disinfectant used for decontamination of vials and bags was expired, and researchers could not remember if they used expired bleach to decontaminate areas after the potential release was identified," reads one section. "Lab workers had not been trained to decontaminate all relevant areas or properly use decontaminants." The inspection found that unidentified "select agent materials" — "select agents" referring to dangerous pathogens — were "transferred within two plastic Ziploc bags between labs, which did not meet the 'durable' requirement for secondary containment."

After the incident, it says, reports were "inaccurate, inconsistent, and incomplete." The CDC reportedly misidentified the number of potentially contaminated specimens, while poor communication made it unclear who was leading the decontamination process and gave conflicting signals. Some supervisors of exposed employees "were advised that their staff should self-monitor rather than visit the clinic," and though the facility was decontaminated, "CDC employees were told they were not in danger." At this point, no employees are believed to have been infected after exposure.

"I want to emphasize how seriously we have taken these incidents."

The anthrax case is only one of a handful of worrying incidents revealed over the past month. While investigating the exposure, the agency discovered that a set of bird flu samples had been cross-contaminated, leading to the temporary closure of the influenza lab and a freeze on transferring biological materials. More worryingly, high-level staff remained unaware of the contamination for months. Earlier in July, vials of viable smallpox were found in an FDA lab. The USDA report notes that other agencies, including the Department of Health and Human Services Office of Inspector General, previously warned that some labs did not adequately vet potential employees or maintain a complete inventory of dangerous materials. In its own report, the CDC described four previous cases in which live anthrax and other dangerous materials were accidentally shipped from its laboratories.

"A potential live anthrax exposure raises serious questions about CDC's adherence to safety protocol measures and the agency's ability to ensure its scientists and the public are safe," said subcommittee head Rep. Tim Murphy (R-PA). CDC director Thomas Frieden, a witness at the hearing, defended the program in testimony, saying that the agency is "uniquely capable" of rapidly identifying and evaluating deadly biological agents that are rarely seen by ordinary clinicians and researchers. Nonetheless, he says the incident "revealed troubling breaches of protocol, gaps in our review systems, and errors in judgment," calling it "unacceptable." Frieden has previously announced a series of steps forward, including creating an advisory board and a central point of accountability for lab safety. "I want to emphasize how seriously we have taken these incidents," he says. "We will do everything possible to live up to the high standards the Congress and the American public rightfully expect us to achieve."