Biosafety level

Essential features of a biosafety level 4 (BSL-4) laboratory^[1]

A biosafety level is a level of the biocontainment precautions required to isolate dangerous biological agents in an enclosed laboratory facility. The levels of containment range from the lowest biosafety level 1 (BSL-1) to the highest at level 4 (BSL-4). In the United States, the Centers for Disease Control and Prevention (CDC) have specified these levels.^[2] In the European Union, the same biosafety levels are defined in a directive.^[3]

History

The first prototype Class III (maximum containment) biosafety cabinet was fashioned in 1943 by Hubert Kaempf Jr., then a U.S. Army soldier, under the direction of Dr. Arnold G. Wedum, Director (1944–69) of Industrial Health and Safety at the United States Army Biological Warfare Laboratories, Camp Detrick, Maryland. Kaempf was tired of his MP duties at Detrick and was able to transfer to the sheet metal department working with the contractor, the H.K. Ferguson Co.^[4]

On 18 April 1955, fourteen representatives met at Camp Detrick in Frederick, Maryland. The meeting was to share knowledge and experiences regarding biosafety, chemical, radiological, and industrial safety issues that were common to the operations at the three principal biological warfare (BW) laboratories of the U.S. Army.^[5][6] Because of the potential implication of the work conducted at biological warfare laboratories, the conferences were restricted to top level security clearances. Beginning in 1957, these conferences were planned to include non-classified sessions as well as classified sessions to enable broader sharing of biological safety information. It was not until 1964, however, that conferences were held in a government installation not associated with a biological warfare program.^[7]

Over the next ten years, the biological safety conferences grew to include representatives from all federal agencies that sponsored or conducted research with pathogenic microorganisms. By 1966 it began to include representatives from universities, private laboratories, hospitals, and industrial complexes. Throughout the 1970s, participation in the conferences continued to expand and by 1983 discussions began regarding the creation of a formal organization.^[7] The American Biological Safety Association (ABSA) was officially established in 1984 and a constitution and bylaws were drafted the same year. As of 2008, ABSA includes some 1,600 members in its professional association.^[7]

Rationale

CDC technician dons an older-model positive-pressure suit before entering one of the CDC’s earlier maximum containment labs.

Biocontainment can be classified by the relative danger to the surrounding environment as biological safety levels (BSL). As of 2006, there are four safety levels. These are called BSL1 through BSL4, with one anomalous level BSL3-ag for agricultural hazards between BSL3 and BSL4. Facilities with these designations are also sometimes given as P1 through P4 (for Pathogen or Protection level), as in the term P3 laboratory. Higher numbers indicate a greater risk to the external environment. See biological hazard.

At the lowest level of biocontainment, the containment zone may only be a chemical fume hood. At the highest level the containment involves isolation of an organism by means of building systems, sealed rooms, sealed containers, positive pressure personnel suits (sometimes referred to as "space suits") and elaborate procedures for entering the room, and decontamination procedures for leaving the room. In most cases this also includes high levels of security for access to the facility, ensuring that only authorized personnel may be admitted to any area that may have some effect on the quality of the containment zone. This is considered a hot zone.

Levels

Biosafety level 1

This level is suitable for work involving well-characterized agents not known to consistently cause disease in healthy adult humans, and of minimal potential hazard to laboratory personnel and the environment (CDC,1997).^[8] Research with these agents may be performed on standard open laboratory benches without the use of special containment equipment and it is not necessary for Biosafety Level 1 labs to be isolated from the general building.

It includes several kinds of bacteria and viruses including canine hepatitis, non-pathogenic Escherichia coli, as well as some cell cultures and non-infectious bacteria. At this level, precautions against the biohazardous materials in question are minimal and most likely involve gloves and some sort of facial protection. The laboratory is not necessarily separated from the general traffic patterns in the building. Work is generally conducted on open bench tops using standard microbiological practices. Usually, contaminated materials are left in open (but separately indicated) waste receptacles. Decontamination procedures for this level are similar in most respects to modern precautions against everyday microorganisms (i.e., washing one's hands with anti-bacterial soap, washing all exposed surfaces of the lab with disinfectants, etc.). In a lab environment all materials used for cell and/or bacteria cultures are decontaminated via autoclave. Laboratory personnel have specific training in the procedures conducted in the laboratory and are supervised by a scientist with general training in microbiology or a related science.

Biosafety level 2

This level is similar to Biosafety Level 1 and is suitable for work involving agents of moderate potential hazard to personnel and the environment.^[8] It includes various bacteria and viruses that cause only mild disease to humans, or are difficult to contract via aerosol in a lab setting, such as C. difficile, most Chlamydiae, hepatitis A, B, and C, human immunodeficiency virus (HIV), orthopoxviruses (other than smallpox), influenza A, Lyme disease, Salmonella, mumps, measles,^[9] scrapie, MRSA, and VRSA. BSL-2 differs from BSL-1 in that:^[10]

1. laboratory personnel have specific training in handling pathogenic agents and are directed by scientists with advanced training;
2. access to the laboratory is limited when work is being conducted;
3. extreme precautions are taken with contaminated sharp items; and
4. certain procedures in which infectious aerosols or splashes may be created are conducted in biological safety cabinets or other physical containment equipment.

Biosafety level 3

Researcher at US Centers for Disease Control, Atlanta, Georgia, working with influenza virus under biosafety level 3 conditions, with respirator inside a biosafety cabinet (BSC).

This level is applicable to clinical, diagnostic, teaching, research, or production facilities in which work is done with indigenous or exotic agents which may cause serious or potentially lethal disease after inhalation.^[8] It includes various bacteria, parasites and viruses that can cause severe to fatal disease in humans but for which treatments exist, such as Yersinia pestis (causative agent of plague), Francisella tularensis, Leishmania donovani, Mycobacterium tuberculosis, Chlamydia psittaci, Venezuelan equine encephalitis virus, Eastern equine encephalitis virus, SARS coronavirus, Coxiella burnetii, Rift Valley fever virus, Rickettsia rickettsii, several species of Brucella, rabies virus, chikungunya, yellow fever virus, and West Nile virus.

Laboratory personnel have specific training in handling pathogenic and potentially lethal agents, and are supervised by competent scientists who are experienced in working with these agents. This is considered a neutral or warm zone.

All procedures involving the manipulation of infectious materials are conducted within biological safety cabinets, specially designed hoods, or other physical containment devices, or by personnel wearing appropriate personal protective clothing and equipment. The laboratory has special engineering and design features.

It is recognized, however, that some existing facilities may not have all the facility features recommended for Biosafety Level 3 (i.e., double-door access zone and sealed penetrations). In this circumstance, an acceptable level of safety for the conduct of routine procedures, (e.g., diagnostic procedures involving the propagation of an agent for identification, typing, susceptibility testing, etc.), may be achieved in a biosafety level 2 (P2) facility, providing

1. the filtered exhaust air from the laboratory room is discharged to the outdoors,
2. the ventilation to the laboratory is balanced to provide directional airflow into the room,
3. access to the laboratory is restricted when work is in progress, and
4. the recommended Standard Microbiological Practices, Special Practices, and Safety Equipment for Biosafety Level 3 are rigorously followed.

The decision to implement this modification of biosafety level 3 recommendations is made only by the laboratory director.

Biosafety level 4

The Galveston National Laboratory BSL-4 (P4) lab on the Campus of the University of Texas Medical Branch

This level is required for work with dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections, agents which cause severe to fatal disease in humans for which vaccines or other treatments are not available, such as Bolivian and Argentine hemorrhagic fevers, Marburg virus, Ebola virus, Lassa virus, Crimean-Congo hemorrhagic fever, and various other hemorrhagic diseases. This level is also used for work with agents such as smallpox that are considered contagious enough to require the additional safety measures, regardless of vaccination availability. When dealing with biological hazards at this level the use of a positive pressure personnel suit, with a segregated air supply is mandatory. The entrance and exit of a level four biolab will contain multiple showers, a vacuum room, an ultraviolet light room, and other safety precautions designed to destroy all traces of the biohazard. Multiple airlocks are employed and are electronically secured to prevent both doors from opening at the same time. All air and water service going to and coming from a biosafety level 4 (or P4) lab will undergo similar decontamination procedures to eliminate the possibility of an accidental release.

Agents with a close or identical antigenic relationship to biosafety level 4 agents are handled at this level until sufficient data are obtained either to confirm continued work at this level, or to work with them at a lower level.

Members of the laboratory staff have specific and thorough training in handling extremely hazardous infectious agents and they understand the primary and secondary containment functions of the standard and special practices, the containment equipment, and the laboratory design characteristics. They are supervised by qualified scientists who are trained and experienced in working with these agents. Access to the laboratory is strictly controlled by the laboratory director.

The facility is either in a separate building or in a controlled area within a building, which is completely isolated from all other areas of the building. A specific facility operations manual is prepared or adopted. Building protocols for preventing contamination often use negatively pressurized facilities, which, even if compromised, would severely inhibit an outbreak of aerosol pathogens.

Within work areas of the facility, all activities are confined to Class III biological safety cabinets, or Class II biological safety cabinets used with one-piece positive pressure personnel suits ventilated by a life support system.

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  Regular inspection of positive pressure suits to locate any leaks^[1]

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  SPECT machine at BSL-4 imaging facility that separates subjects with pathogens from the machines.^[2]

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  The circular containment tube separates the patient table in the "hot" zone (pathogen present) from the "cold" zone around this MRI machine.

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  Air Pressure Resistant (APR) door to separate the hot and cold zones

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  Working inside a BSL-4 lab with air hoses providing positive air pressure.

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  Inside a Class III biological safety cabinet with a aerosol control platform

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  Effluent decontamination system of a BSL-4 lab of NIAID

1. ^ Seligson, Susan (7 March 2013). "Video Offers Glimpse of Biosafety Level 4 Lab Science webcast "threads the NEIDL"". BU Today. Retrieved 5 December 2014. 
2. ^ Cite error: The named reference irf was invoked but never defined (see the help page).

List of BSL-4 facilities

This list is incomplete; you can help by expanding it.

According to the U.S. Government Accountability Office (GAO) report published on October 4, 2007, a total of 1,356 CDC/USDA registered BSL-3 facilities were identified throughout the United States (GAO-08-108T ^[11]). This represents a very conservative estimate of the number of facilities in the US in 2007. Approximately 36% of these laboratories are located in academia. Only 15 BSL-4 facilities were identified in the U.S. in 2007, including nine at federal labs.^[11]

The following is a list of existing BSL-4 facilities worldwide.

See also

• Aeromedical Isolation Team
• Biosafety
• Biocontainment
• Biological hazard
• Hazmat suit
• Laboratory Response Network
• Safety engineering
• Security engineering
• Select agent

Notes and references

External links

• Biosafety in Microbiological and Biomedical Laboratories CDC
• The Sunshine Project: Map of US Biodefense Labs
• Biocontainment laboratories @ the Interpol Bioterrorism Prevention Resource Centre
• Georgia State University's National B Virus Resource Center (BSL4 Lab)
• Karlsruhe Institute of Technology (KIT) - Forschungsstelle für Brandschutztechnik: Research on fire protection and extinguishing systems in microbiological and genetic engineering laboratories.
• Federation of American Scientists: Biosafety Level 3 and 4 Labs
• The 2013 International Conference on Biocontainment Facilities
• eBook Reference: Management Principles for Building and Operating Biocontainment Facilities (Kindle Edition)