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The World Trade Center attacks on September 11, 2001; the CIA’s discovery of biological testing by Al Qaeda; and the recent terrorist bombings in London have certainly changed our perspective not only on disaster preparedness and planning but also on the threat of biological terrorism.

We no longer consider a biological terrorist attack on U.S. soil a remote possibility, rather a reality. For our sake, we hope that is years away, because we have a lot to do to be prepared for minimizing the consequence of such anevent.

Medical examiners will once again play a key role in responding to the next attack, whether involving a threat biologic agent or otherwise. Accordingly, your capacity to respond against potentially biohazardous risks is critical in protecting your life and the lives around you. While preparing for biological terrorism involves addressing some complex issues, the focus of this article is only on biological containment in medical examiner facilities.

Current published biological containment design guidelines relate primarily to research laboratories working with known pathological hazards within highly controlled environments. Researchers in academic, corporate, and government facilities across the county are safely working in well designed biological containment environments with known agents. But what about “unknown” dangers possibly present in medical examiner facilities? Every medical examiner’s office faces the challenge of discovering the unknown threat from mass causalities or a single entity. To do that in most of today’s autopsy/morgue facilities is absurd. This should give you pause to consider how your facility can better prepare you to deal with unknown threats.

How well do biocontainment and biosafety guidelines written for research facilities apply to medical examiners?

The mission of medical examiners and the procedures they use present significantly different challenges. Major differences between medical examiner and research operations with respect to biocontainment and biosafety include:

Hazards are unknown – Probably the biggest differentiator between medical examiners and researchers involves working with unknowns. In research settings, the biological challenges are almost always known or predictable. Medical examiners conduct investigations to determine potential infectious agents.

Human bodies are large – Another difference between medical examiners and most researchers is the physical size of the infectious item. Research often involves procedures that can be contained inside a biological safety cabinet. Medical examiners can’t perform required functions inside a biological safety cabinet.

Human bodies arrive contaminated – Research samples arrive clean, under controlled environments, and then infected in high containment areas. Bodies arrive infected and need to be moved into containment, vehicles delivering bodies need to be disinfected, and the disposal (or disinfection) of bodies is a challenge.

Published Resources
The currently recognized standards and guidelines used in the design of biological containment in research facilities is “Biosafety in Microbiological and Biomedical Laboratories” (BMBL) published by the CDC/NIH. Another document that offers somewhat applicable guidance is USDA’s “ARS Facilities Design Standard 242,” containing special provisions for large animal research facilities. Design of biohazard diagnostic and researchfacilities frequently use both of these standards.

The CDC and the NIH have classified facilities handling hazardous biological agents into four biosafety levels—BSL-1, 2, 3 & 4—that correspond to specific operations performed, transmission of infectious agents, and facility functions. Each represents a different combination of primary and secondary barriers that provide increasing levels of protection for personnel and the outside environment. Primary barriers are good laboratory practices and techniques (along with administrative controls) and safety equipment. Secondary barriers are facility design and construction. A risk assessment of the work performedwith a specific agent will determine the appropriate combination of these elements.

BSL-3 has well defined minimum facility design requirements, but stipulates a risk assessment to determine the need for additional containment measures. When the autopsy process introduces the need for biological containment, BSL-3 best suits this scenario. Determining the features required to meet the risks specific to medical examiner facilities is a challenge faced in the design of a modern medical examiner facility.

Two published papers that provide excellent documentation on primary containment issues specific to medical examiner operations include:

• “Biosafety Considerations for Autopsy,” K. Nolte, D. Taylor, J.Richmond; AJFMP, June 2002, 23(2):107-22

• “Medical Examiners, Corners, and Biologic Terrorism – A Guidebook for Surveillance and Case Management,” K. Nolte, R. Hanzlick, D. Payne, A. Kroger, W. Oliver, A. Baker, D. McGowan, J. DeJong, M. Bell, J. Guarner, W, Shieh, S. Zaki; MMWR June 11, 2004 / 53(RRo8);1-27

Both of these papers also reference the CDC publication BMBL for facility requirements related to secondary containment.

Personnel and Materials Flow
Fundamental to biological containment design is establishing the secondary containment barrier and providing a method of controlling and safely moving personnel, gurneys, bodies, samples, utilities, scientific equipment, information, and supplies through it. From staff to services, bodies to specimens, good facility design establishes the proper flow of personnel and materials to maintain biological containment. Of course the facility is only a part of the solution. Operations, training, and safety equipment (PPEs) are extremely important for effective containment. However, a well designed biological containment facility will help promote the best practices in every aspectof your daily operations.

Highly trained personnel must have appropriate facilities for gowning before getting into the containment area, working within, and then exiting the environment (de-gowning). Like the layers of an onion, moving in and out of the containment zone must be through a series of rooms. As with an onion, each layer or room has a protective membrane surrounding it. Having a series of rooms that allows staff to don personal protective gear in several steps prepares them both physically and mentally for entering the hot zone.

The rooms’ finishes are very monolithic—clean, smooth, few edges, and corners and tightly sealed. Ceilings are flat, smooth, and hard (not a laid-in product) with surface-mounted light fixtures. Entry and exit rooms should have interlocking doors. Interlocking prevents both doors opening at the same time, thus averting a breach in containment. To control access into containment areas, a keypad security system is necessary. Proximity card systems would mean taking a card into the containment area, and then having to exit with a contaminated card. In the near future, biometrics will more commonly control access.

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One must approach the containment area (CA) through an airlock. Once in the airlock, you notice signage warning of the potential dangers upon entering the CA. An airlock maintains the proper directional air flow between the area outside of containment and into the CA. When the door closes behind you, you are entering a pressurized space, with each successive room becoming more negative until you reach the main autopsy area. The main autopsy room (containment area) will have the most negative pressure relative to all other spaces to prevent pathological hazards from leaving the CA.

Next is the locker room. This space could be unisex, if staff is already wearing surgical scrubs and need only to don protective garments. If not, male and female dressing rooms may be an appropriate first step. The locker room has the same finishes and hardware as the airlock. Furniture in the locker room includes a sitting bench, shelving or cabinets for storing protective gear, lab coat hooks, trash can, sink, hand dryer, and mirror. If designed properly, the airlock and locker room could be used as entry and exit for the CA. A locker room could also have private toilets.

The final room before entering the CA is the gowning room. This room holds the respirators and protective outer gear required for the staff. This unisex room allows staff to assist each other with gowning and a final PPE check before entering the contained work area.

The work area is just that; it is all the space necessary for supporting the autopsy activities of death investigation. These spaces follow the same design philosophy as the entry and exit pathways, including similar materials and finishes. The lack of sharp edges or exposed corners is very obvious.

Decontamination
Everything that goes into the containment area must eventually come out. Therefore, water, air, people, PPEs, bodies, samples, scientific equipment, gurneys, information, and disposables all must be decontaminated before safely removed from the containment area. A provision for the disinfection of liquid and biological wastes is common in containment areas. Either heat or chemical disinfection renders safe liquid drainage. These systems often employ multiple tanks to collect and then disinfect drainage. Solid biological waste is either red bagged or disposed of through alkaline digesters. Alkaline digesters offer an effective biological kill and liquefy the solid biological waste for disposal down the sanitary sewer drain. Red bagged waste first needs to be externally disinfected before removal from the work area, and thensuitably disposed.

Pass-through autoclaves are effective devices to disinfect disposables, PPEs, and gowns removed from the containment area. Equipment removed from containment is placed in a fumigation airlock, which is sealed and uses a gaseous disinfectant. Once the cycle is completed the airlock can then be open from the outside of containment and the equipment removed.

Removal of human bodies from containment poses unique challenges. Techniques in research settings that use alkaline digesters for the disposal of animal carcasses present obvious cultural problems. Certainly the ability to externally decontaminate sealed body bags with liquid disinfectants and then fumigate the body and gurney in airlock allows for safe removal from containment. Ultimate handling of the remains is a question outside the focus of this article.

Engineering Controls
Ventilation systems are important in maintaining the containment barrier. Ventilated air brought into containment needs to be properly conditioned and controlled. Carefully controlling the amount of air supplied to containment areas relative to the amount of air removed assures negative pressure within containment spaces and positive pressure in surrounding areas. Special features that interlock air systems inside containment with entry airlocks to assure correctair flow directions when doors open are often required.

Air from containment areas may need HEPA (High Efficiency Particulate Air) filtration to remove any airborne hazards before being exhausted from the building. Ductwork serving the containment areas is often equipped with tight sealing dampers to allow isolation of the containment area itself for gaseous decontamination.

Systems and devices necessary to achieve ventilation controls need to be of high quality, designed to allow maintenance from outside of containment, and have appropriate standby provisions to assure system integrity and reliability. Ventilation system configuration is very important for the safety of maintenance personnel.

Piped utilities (power, plumbing, data, etc.) brought through the containment barrier to supply the containment area must be effectively sealed. Techniques employed to create this seal include welding to flanges imbedded in concrete walls to seal any gap, filling electrical conduits with epoxy, and individual back flow prevention in water piping. Sealing penetrations is very important in high level containment.

Testing prescribed by some published containment guidelines requires the containment area brought to a significant negative pressure within and held for an acceptable pressure decay range and period. These tests can literally pull the paint off the wall.

Conclusion
Biocontainment and biosafety standards and guidelines written for research are a good start for medical examiner facilities. Certainly the techniques employed in research settings provide good guidance. Maybe the next questionis: should we establish separate guidelines for medical examiner facilities?

Hopefully this article spurs discussion about requirements for biocontainment autopsy facilities. We must expand current design standards for biological containment to create the correct environment for medical examiner facilities. It’s all about being prepared and knowing your facility’s limitations for dealing with the “unknown.”

Lou Hartman is a Principal and Sr. Mechanical Engineer with HarleyEllis, and Ken Mohr is a Principal and Sr. Forensic Laboratory Planner with HERA, Inc. His 17 years of experience with advanced laboratories includes nearly 3 million square feet of forensic facilities. HarleyEllis and HERA together form a strategic alliance called Crime Lab Design, which provides full A/E services for forensicand medical examiner facilities. Ken can be reached at kmohr@herainc.com

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