Biosafety Level 4 is required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections and life-threatening disease that is frequently fatal, for which there are no vaccines or treatments, or a related agent with unknown risk of transmission. Agents with a close or identical antigenic relationship to agents requiring BSL-4 containment must be handled at this level until sufficient data are obtained either to confirm continued work at this level, or re-designate the level. Laboratory staff must have specific and thorough training in handling extremely hazardous infectious agents. Laboratory staff must understand the primary and secondary containment functions of standard and special practices, containment equipment, and laboratory design characteristics. All laboratory staff and supervisors must be competent in handling agents and procedures requiring BSL-4 containment.Now, the CDC has issued its internal report on the December, 2014 Ebola incident in which a lab worker was possibly exposed to live Ebola virus. The report is detailed, and it is clear that human error explains the incident where Ebola virus may have been unintentionally transferred from a BSL-4 lab to a BSL-2 lab, which would lack the same degree of protection for potentially exposed workers. An earlier internal CDC report on the June, 2014 anthrax incident, involving transfer of a biological sample from a BSL-3 to a BSL-2 lab also identified personnel errors, as well as gaps in the overall containment protocols. In August, 2014, as a result of the pattern of safety lapses, the White House ordered a stand-down for federal laboratories to pause and review their biocontainment policies and practices, as well as perform an audit of pathogens and select agents. Reports now issued by the CDC and NIH detail the result of the stand-down, detailing the scale and site of research with the most dangerous pathogens, and identifying instances where undocumented biological samples have been left behind from earlier investigations. Overall, the stand-down produced a real-time status report on pathogen storage and handling in the leading federal labs; it is clear from the specific incidents reports, however, that human error can still override the most carefully planned containment measures.
February 9, 2015
CDC Reports on Ebola Virus and Anthrax Safety Lapses in Its Laboratories; Federal Audit Results
Over the last year, reports of biosafety lapses in federal laboratories conducting research on anthrax, smallpox and Ebola virus elicited strong reactions in the scientific community and generated official responses to reduce the likelihood of similar events (see here for overview of CDC, NIH and FDA incidents). As the nation's signature public health agency, the incidents at the CDC laboratories were especially troublesome. In general, laboratories conducting microbiological research are designed to accommodate the safety requirements attendant to the threat of the pathogen itself. The safety evaluation will mandate the appropriate facilities, procedures and trained personnel based on the level of risk Laboratories are classified in a tier of biosafety levels (BSL1-4), with a BSL-4 designation describing the highest level containment environment: