What is the lowest BSL that requires all manipulations of biohazards to take place within biological safety cabinets or other primary containment?
Biobanking. 2019; 1897: 213–225. Guest Editor (s): William H. Yong Division of Neuropathology, Department of Pathology and Laboratory Medicine, Brain Tumor Translational Resource, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, CA USA William H. Yong, Phone: +11310-825-8269, Fax: +11310-825-7353, Email: ude.alcu.tendem@gnoyw. When it comes to biobanking and working with different types of laboratory specimens, it is important to understand potential biohazards to ensure safety of the operator and laboratory personnel. Biological safety levels (BSL) are a series of designations used to inform laboratory personnel about the level of biohazardous
risks in a laboratory setting. There are a total of four levels ranked in order of increasing risk as stipulated by the Center of Disease Control and Prevention (CDC) (Biosafety in microbiological and biomedical laboratories, 5th edn. HHS publication no. (CDC) 21-1112. https://www.cdc.gov/biosafety/publications/bmbl5/bmbl.pdf. Accessed 2 Jan 2016, 2009). We will address the main distinctions between these levels including briefly introducing hazards characteristics that classify biohazardous agents, as well as define the essentials in meeting safety requirements. Key words: Biosafety, Safety requirements, Biohazard, Biosafety levels, Personal protective equipment BSLs are a series of safety precautions that will help reduce laboratory personnel’s risk of exposure to potentially infectious biohazardous agents. There are four biosafety levels that are implemented and defined by the CDC. Each biosafety level has specific containment controls, which include microbiological practices, safety equipment, and facility safeguards to protect laboratory workers , the public and the environment from exposure to infectious
biohazards that are used in the lab. These containment controls build on the preceding level of safety, in a pyramid-like fashion, as the risk level increases. Biosafety levels dictate the type of work practices that are allowed to occur in a lab setting and play a huge role in the design of the facility. Risk assessment plays an important role in determining the biosafety level of a lab. The CDC defines
risk assessment as the process by which the appropriate selection of practices and safe guards respective of the agents are implemented to prevent laboratory-associated infections. Risk assessment is bound by two main categories: agent hazards and laboratory procedure hazards. Similarly, the main determinants of biosafety levels are dependent on the work performed in the laboratory as well as the agents used. Mainly, the following parameters are considered during the risk assessment process: Infectivity—the ability of a pathogen to establish an infection or a pathogen’s capacity for horizontal transmission, Transmissibility, and Nature of work conducted. Specifically, when investigating biohazardous agents that will be handled and manipulated by the laboratory, risk assessment involves scrutinizing the principal hazardous characteristics of an agent. These include: Capability to infect and cause disease
in a susceptible human or animal host. Virulence as measured by the severity of the resulting disease. The availability of preventive measures and effective treatments for disease Additional characteristics of hazardous agents include route of transmission of laboratory infection, infective dose, stability of agent in the environment, host range, and its endemic nature. All these factors contribute to the respective agent’s
risk assessment. The World Health Organization (WHO) has established a risk group classification for hazardous agents used in a biomedical setting [1]. These agents are stratified mainly based on the route of transmission of the natural disease. It is important to note that these four risk group classifications do not equate to biosafety levels implemented in a laboratory setting. There are four biosafety levels that are implemented and defined by the CDC. Biosafety levels are an important and integral part of biohazardous communication and training for work in these facilities. Most institutions have biosafety review boards and committees that ensure that these guidelines are followed and can often address laboratory-specific questions. Clinical work involving human specimens are generally
characterized under BSL2 guidelines, though oftentimes the infectious natures of clinical specimens are unknown. BSL2 level of compliance aligns well with Occupational Safety and Health Administration (OSHA) (the oversight body for enforcement of safety and health legislation) standard when working with specimens that contain blood or blood traces [2]. Strict adherence to guidelines and suggestions
given by the CDC will help communicate a safer workspace and promote compliance in the laboratory. This chapter addresses biosafety level distinction and classification in a standard laboratory but does not address the specific guidelines that are given for vertebrate animal biosafety level criteria. A thorough and comprehensive exploration of biosafety levels, safety practices, and regulatory standards for animal biosafety levels could be found in the CDC’s Biosafety in Microbiological and
Biomedical Laboratories [3]. Biosafety level 1 (BSL1) is the lowest risk level and involves work and procedures performed with established and characterized strains of microbes that are not known to consistently cause disease in healthy adult humans. These agents generally pose minimal threat to environment. Examples of these
microbes include: Bacillus subtilis, Naegleria gruberi, S. cerevisiae, and E. coli. Research conducted in BSL1 laboratories is generally performed on open laboratory benches without the need for special containment. The CDC advises standard microbiological practices to be followed which are described below. Hand washing is required after working/handling potentially hazardous
materials and before leaving the laboratory Eating, drinking, smoking, handling contact lenses, applying cosmetics, and storing of food are not permitted in laboratory areas. Refrigerators and freezers used in the laboratories must be clearly labeled for laboratory use only. Mouth pipetting is prohibited. Reduced use of sharps, such as glass Pasteur pipettes, needles, and scalpels, is advised including the implementation of engineering controls and
proper use of sharps needles (no recapping of needles, disposal of used needles in puncture-proof containers etc.). Minimize the creation of splashes and aerosols. Decontamination of work surfaces after work with microbial/other BSL1 designated agents. Safety Equipment for BSL1BSL1 labs do not require special containment equipment like biological safety cabinets. The following are a list of primary barriers and personal protective equipment that are used in a BSL1 setting:
Laboratory Facilities for BSL1
Biosafety Level 2Biosafety level 2 (BSL2) builds on the safety precautions and procedures of BSL1. Biohazardous agents that are under BSL2 pose moderate hazards to the environment and to laboratory personnel if accidentally exposed by skin contact, inhalation, or ingestion. Examples of BSL2 hazardous agent are Staphylococcus aureus, Salmonella, and human cell lines. BSL2 labs differ from BSL1 lab by the additional necessary training specific for handling BSL2 pathogenic agents. These laboratories also have restricted access to workspaces where BSL2 hazardous agents are handled, used, and manipulated. Lastly, all procedures where infectious or possibly infectious aerosols/splashes could be created are conducted in biological safety cabinets (BSC). BSL2 Procedures and Practices
Safety Equipment for BSL2BSL2 laboratories include all of the safety equipment and precautions used for BSL1 labs. This includes all engineering controls, safety equipment, and any special laboratory facilities. The following are a list of primary barriers and personal protective equipment that are used in a BSL2 setting.
Laboratory Facilities for BSL2
Biosafety Level 3Biosafety Level 3 (BSL3) builds on the safety precautions and procedures of BSL1 & 2. This includes all engineering controls, safety equipment, and any special laboratory facilities. Biohazardous agents that are under BSL3 are indigenous, exotic and may cause serious or lethal disease through respiratory transmission. Examples of BSL3 hazardous agents are Mycobacterium , SARS coronavirus, Chlamydia psittaci, etc. BSL3 labs differ from BSL2 labs by the nature of transmission of hazardous agents. BSL3 labs also require the added precaution of directional airflow (negative air flow) to ensure that air flows from nonlaboratory areas into laboratory areas. BSL3 Procedures and Practices
Safety Equipment for BSL3
Laboratory Facilities for BSL3
Biosafety Level 4Biosafety Level 4 (BSL4) laboratories are the highest level of biological safety, and are very rare. They are usually separate facilities that are physically disconnected from other facilities and sufficiently isolated. They build on the safety precautions and procedures of BSL1, 2, and 3 laboratories. This includes all engineering controls, safety equipment, and any special laboratory facilities. Biohazardous agents that are under BSL4 are dangerous and exotic and pose a high risk through aerosol/respiratory transmission in the laboratory that can lead to life-threatening disease and are lethal. Vaccines and treatments are generally not available for these agents. Some investigated agents in which routes of transmission remain unclear are given BSL4 designation. Examples of BSL4 hazardous agents include Ebola, Marburg, and Lassa Viruses and Crimean-Congo hemorrhagic fever. BSL4 labs differ from BSL3 labs by the specific training required by laboratory personnel and staff in handling extremely hazardous infectious agents. This is inclusive of primary and secondary containment and all standard and special practices that involve handling, manipulation, and storage of these dangerous BSL4 agents. BSL4 laboratories are divided into two types, cabinet laboratories and suit laboratories. The differences between the two as well as addition BSL4 specific protective measures will be discussed in detail below. BSL4 Procedures and Practices
Safety Equipment for BSL4Cabinet laboratory: All work involving infectious materials in the laboratory must be conducted in a Class III BSC. Specific class III BSC protocols include:
Suit : All work conducted in a BSL4 suit laboratory must be conducted in a one-piece positive pressure supplied air suit.
Laboratory Facilities for BSL4Cabinet laboratories facility requirements:
Suit laboratory facility requirements: They have the same requirements as cabinet laboratories and include additional provisions:
ReferencesWhat is the lowest BSL that requires all manipulations of biohazards to take place within biological safety cabinets?BSL-1 is the lowest security level for handling biological material.
What are BSLBSL-2 laboratories are used to study moderate-risk infectious agents or toxins that pose a moderate danger if accidentally inhaled, swallowed, or exposed to the skin. Design requirements for BSL-2 laboratories include hand washing sinks, eye washing stations, and doors that close and lock automatically.
What does BSLBSL-1. If you work in a lab that is designated a BSL-1, the microbes there are not known to consistently cause disease in healthy adults and present minimal potential hazard to laboratorians and the environment. An example of a microbe that is typically worked with at a BSL-1 is a nonpathogenic strain of E. coli.
What are the 4 BSL levels?The four biosafety levels are BSL-1, BSL-2, BSL-3, and BSL-4, with BSL-4 being the highest (maximum) level of containment. There are additional specific rules and designations for animal research (ABSL), agricultural research (BSL-Ag), and other types of research.
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