Ever since an anthrax attack shut down the U.S. House of Representatives in October 2001, state public health laboratories have been gearing up for their new role as America's first line of defense against bioterrorism.
Historically, state labs have performed such tasks as testing for diseases among newborns and analyzing food-borne pathogens. But identifying and handling substances as toxic as the Ebola virus and aerosolized anthrax require more secure facilities than most states had prior to the events of September and October 2001.
Jim Riley, AIA, a lab planning specialist with the Atlanta office of the science and technology design firm CUH2A, has consulted on or has been involved with design of 15 recent public health labs, including facilities in Virginia, Arizona, Minnesota, North Dakota, and Oregon.
"What we play with here can, in some cases, kill you," Riley said. "We try to achieve the right blend of paranoia and practicality."
Riley approaches each facility with an eye toward the future. "We have a simple mantra: open labs where possible, closed labs where required," he said. "The mix is different in every location."
Open labs accommodate day-to-day high-volume testing work, designated by the Centers for Disease Control and Prevention as a biosafety level one (BSL-1) or BSL-2 threat (see p. 56). According to Riley, the baseline for public health labs is moving toward BSL-2.
Closed labs handle more hazardous BSL-3 and BSL-4 work. Open labs need to be designed to allow rapid change in layout and function.
"The rate of change faced by these labs is incredible," Riley said. "Everything is constantly evolving, and methods are changing with the new demands placed on labs by the FBI and state police. Public health labs now have to worry about things like evidentiary chains of custody, and handle BSL-3 and even BSL-4 work."
Riley says the closed BSL-3 labs are not designed as hermetically sealed boxes, but rather rely on engineered airflow and primary containment devices like biosafety cabinets to contain hazardous agents.
"Level four labs are in fact hermetically sealed boxes," Riley said. "But the degree of precision in the ventilation systems cannot be underestimated. That is something we have to work on closely with contractors. With both enclosed and open space, we are venting more air from the lab than we are supplying, and every six minutes the air in the building is replaced. That means that if there is an accident in one of the enclosed labs, the material will not be carried by the air into the rest of the building."
The enclosed labs are vented through HEPA and sometimes HEGA filters before being exhausted to the exterior of the building.
Ease of clean-up in enclosed lab spaces is also critical. "If someone drops a container of fine white powder that might be aerosolized anthrax, suddenly the coping of the sheet vinyl in the floor becomes very important," Riley said.
Communication with nearby communities also demands attention.
"When done right, these labs provide a high degree of safety," Riley said. "But not everyone has the same level of scientific knowledge. One has to be sensitive to the needs of the community."
Riley offers the following advice:
Lay out buildings as a flow diagram. Plan for a central accessioning area designed for the highest possible threat level until triage can take place. "You are dealing with millions of specimens coming in a year, and you need to think about high volume with unique hazards embedded within," Riley said. These specimens flow through a central accessioning area where lab workers separate known substances from highly hazardous and unknown specimens, he said.
Design for lab hazards. Biological, chemical, radiological, and physical hazards like gas cylinders all require specific safeguards; as a result, design of the lab will depend on the nature of materials to be handled in that lab.
"BSL-3 is a good example," Riley said. "It can be simple or it can be almost as stringent as BSL-4, depending on the nature of hazards to be handled."
Riley said public health labs will vary widely in the amount of space devoted to radiological threats. "At the Minnesota public health lab, the central accessioning area features three separate areas for chemical, biological, and radiological threats," Riley said, while Indiana and Virginia have a smaller percentage of space devoted to radiological studies.
States with significant nuclear facilities will require more space devoted to radiological threats, particularly if other government agencies do not have similar facilities, according to Riley.
Design for safety. Make sure there are two exits from any workspace and allow workers to see and be seen for safety.
Allow for multi-tiered flexibility. On past projects, CUH2A has provided for future instrumentation changes by specifying overhead service carriers for lab utilities, such as gases and ventilation. This eliminates fixed-position benches that would normally provide these utilities, allowing lab equipment to be changed more easily.
Create a productive work environment. Older public health labs tend to be drab, windowless structures. Simple daylighting and window access make for a much more cheerful workplace. Locating labs around common areas can also create a collegial atmosphere.