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Is it safe? Lab design and maintenance key
Two cautionary tales underscore risk
As the number of high-containment labs undergoes an unprecedented expansion in the United States, the question of relative risk is coming to the forefront.
Some of the scenarios have "cold war" overtones updated for a new age of a bioterror. For example, a worker intentionally removes a pathogenic agent. Similarly, the facility itself could be a target for terrorist attack designed to cause massive disruption and panic. On a more pragmatic level, lab workers face the daily risk of infection — and potential spread to the surrounding community — if they breach infection prevention protocols or the lab suffers some systems failure that leaves them vulnerable. Such research facilities — biosafety level (BSL)-4 labs in particular — have redundant engineering systems to ensure they live up to their name: "high containment." But two incidents last year reveal that relatively mundane events could open the door to compromised controls and potentially threaten workers and/or the community at large.
According to a report by the General Accountability Office (GA0) on June 8, 2007, the Centers for Disease Control and Prevention campus in Atlanta experienced lightning strikes in and around its new BSL-4 facility.1 Both primary and backup power to that facility failed, leaving only battery power for functions such as elevators and emergency lighting to aid in evacuation. "Among other things, the outage shut down the negative air pressure system, one of the important components in place to keep dangerous agents from escaping the containment areas," the GAO reported.
CDC told the GAO that the new BSL-4 facility was still in preparation to become fully operational and no live agents were inside the facility at the time of the power outage. In looking into the power outage, the CDC determined that, some time earlier, a critical grounding cable buried in the ground outside the building had been cut by construction workers digging at an adjacent site. The cutting of the grounding cable, which had gone unnoticed by CDC facility managers, compromised the electrical system of the facility that housed the BSL-4 lab. "It is apparent that the construction was not supervised to ensure the integrity of necessary safeguards that had been put in place," the GAO noted. "The incident raised questions about safety and security, as well as the backup power system design. The incident showed that, even in the hands of experienced owners and operators, safety and security of high-containment labs can still be compromised. The incident also raises concerns about the security of other similar labs being built around the nation."
The CDC is doing a reliability assessment for the entire campus power system, which will include the backup power design for the new BSL-4 facility. Some experts have suggested that BSL-4 labs be similar in design to a nuclear power plant, with a redundant backup-to-backup power system, along with adequate oversight. "Like such plants, BSL-4 labs are considered targets for terrorists and people with malicious intent," the GAO warned. "Release of an agent from any of these labs could have devastating consequences. Therefore, appropriate design of labs and adequate oversight of any nearby activities — such as adjacent construction with its potential to compromise buried utilities — are essential."
The importance of maintenance
While the CDC experienced a problem during new construction, another incident underscores the need for ongoing maintenance of high-containment facilities. Because the labs may contain microorganisms in liquid or aerosol form, even minor structural defects such as cracks in walls, leaky pipes, or improper sealing around doors could have severe consequences. Supporting infrastructure, such as drainage and waste treatment systems, also must be secure, the GAO emphasized.
In August 2007, contamination of foot-and-mouth disease was discovered at several local farms near Pirbright in the United Kingdom, the site of several high-containment labs that work with live foot-and-mouth disease virus. Foot-and-mouth disease is one of the most highly infectious livestock diseases and can have devastating economic consequences. "The investigation of the physical infrastructure at the Pirbright site found evidence of long-term damage and leakage of the drainage system servicing the site, including cracked and leaky pipes, displaced joints, debris buildup, and tree root ingress," the GAO reported. "While the definitive cause of the release has not been determined, it is suspected that contaminated waste water from Pirbright's labs leaked into the surrounding soil from the deteriorated drainage pipes and that live virus was then carried off-site by vehicles splashed with contaminated mud."
The Pirbright incident shows that beyond initial design and construction, ongoing maintenance plays a critical role in ensuring that high-containment labs operate safely and securely over time, the GAO concluded.