On This Page On This Page AUTOCLAVING 101 Learn how to safely and confidently operate an autoclave with our free training course. Start the Course Biosafety Levels 1, 2, 3 & 4: What’s the Difference? Written by: Arthur Trapotsis MS Biochemical Engineering, MBA, Consultant Updated 11/3/22: Information about the biosafety level requirements for handling SAR-CoV-2 (COVID-19 coronavirus) can be found here. Safety is of the utmost importance in any laboratory setting, especially when working with autoclaving equipment. In order to ensure the safety of lab personnel, the environment and surrounding communities, the Centers for Disease Control and Prevention (CDC) have defined biosafety levels — each with corresponding safety protocols — for different types of facilities. In this blog post, we’ll explain what those biosafety levels are, how they’re defined, what precautionary measures lab workers need to take for each level, and more. What Are Biosafety Levels? Biological safety levels — often abbreviated to biosafety levels or BSL — are a series of protections specific to autoclave-related activities that take place in biological labs. Biosafety levels are individual safeguards designed to protect laboratory personnel, as well as the surrounding environment and community. Download our BSL Quick Reference Guide Here > These levels, which are ranked from one to four, are designated based on the biohazards (such as agents or organisms) laboratory personnel encounter in the lab. For example, a basic lab setting that specializes in the research of non-lethal agents that pose minimal threat to lab workers and the environment would generally be considered BSL-1, which is the lowest biosafety level. By way of comparison, a research laboratory that specializes in handling potentially deadly infectious agents, such as the Ebola virus, would be designated as a BSL-4 lab — the highest and most stringent biosafety level. It’s also important to keep in mind that while sometimes used interchangeably, biohazard levels are distinct from biosafety levels. To clarify, biohazard levels are used to classify agents based on the risk they pose to human life. BSLs, on the other hand, focus on the precautions that labs need to take to protect staff from these biohazards. This means that lab personnel can expect to encounter level one biohazards in a BSL-1 environment, level two biohazards in a BSL-2 setting, and so on. How Are Biosafety Levels Defined? The CDC sets biosafety levels to indicate what specific controls a laboratory must have in place for the containment of microbes and biological agents. Each biosafety level builds upon the previous level, thereby creating layer upon layer of constraints and barriers. Each biosafety level — BSL-1 through BSL-4 — is defined based on the following: Risks related to containment Severity of infection Transmissibility Nature of the work conducted within the lab Origin of the microbe Agent in question Route of exposure More specifically, when determining BSLs for different agents and microbes, the Centers for Disease Control and Prevention (CDC) recommends performing a biological risk assessment. This process involves taking the following steps to address agent and protocol risks: Identify the agent’s hazardous characteristics: Assess the agent’s ability to cause disease, severity, transmission routes, infectious dose, stability, and host range. Identify laboratory procedure hazards: Determine the risks presented by handling techniques; equipment use; aerosol generation; and exposure routes such as skin contact, ingestion, inhalation, and needle sticks. Determine the appropriate BSL: Select the necessary BSL based on risk assessment, factoring in safety precautions, facility safeguards, and regulatory requirements. This determination is typically made by a group that includes a principal investigator, institutional biosafety professionals, and biosafety committees. Biosafety levels dictate the types of work practices allowed to take place in a lab setting; they also heavily influence the overall design of a facility and the type of specialized safety equipment in it. Get Your Safety Tips Checklist for BSL Labs 1–4 Here > Biosafety Level 1 (BSL-1) The lowest of the four biosafety levels, biosafety level 1 (BSL-1) applies to laboratory settings in which personnel work with low-risk microbes that pose little to no threat of infection in healthy adults. Because of this, BSL-1 labs typically do not need to be isolated from surrounding facilities. Types of Agents Studied Some examples of the microbes handled in biosafety level-1 labs include: Chicken pox Non-infectious types of bacteria Nonpathogenic strains of E. coli Commonly Used Equipment As the lowest biosafety level, BSL-1 labs don’t require the use of specialized equipment to carry out research, which is typically conducted on benches. Surfaces should be easy to clean and able to tolerate standard laboratory chemicals. Safety Protocols Safety protocols for biosafety level 1 labs — which require only basic microbial practices — include: Mechanical pipetting (no mouth pipetting allowed) Safe sharps handling Avoidance of splashes or aerosols Daily decontamination of all work surfaces when work is complete Regular handwashing Prohibition of food, drink, and smoking materials The use of personal protective equipment (PPE), such as goggles, gloves, and a lab coat or gown Biohazard signs BSL-1 labs also require immediate decontamination after spills. Infectious materials should also be decontaminated prior to disposal, generally through the use of an autoclave. Biosafety Level 2 (BSL-2) Biosafety level 2 (BSL-2) covers all laboratories that work with agents associated with human diseases — that is, pathogenic or infectious organisms — that pose a moderate health hazard if inhaled, ingested, or exposed to the skin. BSL-2 labs must follow the same standard microbial practices as BSL-1 labs while also implementing additional precautions to address the higher risk associated with the agents they study. Personnel working in biosafety level 2 laboratories are expected to take even greater care to prevent injuries, such as cuts and other breakage to the skin, as well as ingestion and mucous membrane exposures. Types of Agents Studied BSL-2 labs might study the following: Dengue Equine encephalitis viruses Hepatitis A, B, and C HIV Lyme disease Measles Mumps Salmonella Staphylococcus aureus (staph infections) Commonly Used Equipment Given the nature of the agents present in BSL-2 labs, workspaces must have access to equipment capable of decontaminating waste, such as incinerators and autoclaves (or another decontamination method). Additionally, all procedures that could cause infection from aerosols or splashes must be performed within a biological safety cabinet. Safety Protocols In addition to the safety protocols established for BSL-1 labs, BSL-2 labs are subject to the following safety controls: The use of PPE, including lab coats, gloves, eye protection, and — in some cases — face shields Decontamination of infectious materials prior to disposal, generally through the use of an autoclave Self-closing, lockable doors Access to a sink and eyewash station Biohazard warning signs Access to a biosafety level 2 lab is far more restrictive than to a biosafety level 1 lab. Outside personnel, or those with an increased risk of contamination, are often restricted from entering the area while work is underway. Get our BSL Quick Reference & Safety Tips Guide Here > Biosafety Level 3 (BSL-3) Once again building on the two prior biosafety levels, a biosafety level 3 (BSL-3) laboratory typically conducts research into or work on microbes that are either indigenous or exotic and can cause serious or potentially lethal disease through inhalation. Types of Agents Studied Common examples of microbes found in BSL-3 labs include: Anthrax COVID-19 Hantavirus Malaria Mycobacterium tuberculosis Rift Valley fever Rocky Mountain spotted fever West Nile virus Yellow fever Commonly Used Equipment To ensure the safety of laboratory staff, biosafety cabinets, incinerators, autoclaves, and a sustained directional airflow system — to draw air into the laboratory from clean, non-laboratory areas toward potentially contaminated areas — must be present. Safety Protocols Microbes found within biosafety level 3 settings are so serious that work is often strictly controlled and registered through the appropriate government agencies. Laboratory personnel are also under medical surveillance and may require immunizations for the microbes they work with. Common safety controls within a BSL-3 lab include: The use of PPE, including goggles and gloves; respirators may also be required The use of solid-front wraparound gowns, scrub suits, and/or coveralls is often required Access to a hands-free sink and eyewash station available near the exit Self-closing set of locking doors with access away from general building corridors Access to a BSL-3 laboratory is restricted and controlled at all times. Biosafety Level 4 (BSL-4) Biosafety level 4 (BSL-4) labs are rare; however, a small number exist in the U.S. and around the world. As the highest level of biological safety, BSL-4 labs work with highly dangerous and exotic microbes. Infections caused by these types of microbes are often fatal and come without treatment or vaccines. Types of Agents Studied Agents present in BSL-4 labs might include: Bolivian hemorrhagic fever (or other tropical hemorrhagic fevers) Ebola virus Lassa fever Marburg virus Commonly Used Equipment Since biosafety level 4 labs deal with the most dangerous agents, they are required to house advanced equipment that enables researchers to safely carry out their studies. All BSL-4 environments must provide access to class III biosafety cabinets and be equipped with dedicated air supply and exhaust air (plus vacuum lines and decontamination systems). Safety Protocols In addition to biosafety level 3 considerations, biosafety level 4 laboratories must follow these safety protocols: Personnel must change clothing before entering the facility and shower upon exiting All materials must be decontaminated before leaving the facility Personnel must wear the PPE from lower BSL levels, as well as a full-body, air-supplied, positive pressure suit BSL-4 labs are extremely isolated, often located in an isolated and restricted zone of a building or in a separate building entirely. BSL-4 labs also feature a dedicated supply of exhaust air, as well as vacuum lines and decontamination systems. Get our BSL Quick Reference & Safety Tips Guide Here > Additional Biosafety Levels In addition to the biosafety levels previously discussed, specialized biosafety classifications exist for certain types of research. Two key examples are Animal Biosafety Levels (ABSL) and Agricultural Biosafety Levels (BSL-Ag), which are designed to address the unique risks associated with animal and agricultural research. Animal Biosafety Levels ABSL classifications are used in research involving animals that carry or are infected with potentially hazardous biological agents. These levels — ABSL-1 through ABSL-4 — align with traditional BSLs, but include additional containment measures to protect researchers, prevent cross-contamination, and ensure animal welfare. ABSL-1: Used for research involving animals that carry well-characterized agents that aren’t known to cause disease in humans. ABSL-2: Research involves animals infected with agents that pose moderate health hazards to humans, such as certain viruses, bacteria, and parasites. ABSL-3: Labs work with animals infected with agents that can cause serious or potentially lethal disease in humans as well as agents that spread through aerosol transmission, such as Mycobacterium tuberculosis. ABSL-4: Denotes a laboratory environment where researchers work with animals infected with highly dangerous pathogens that cause life-threatening disease, pose a high risk of aerosol transmission, or have an unknown transmission risk. Agricultural Biosafety Levels BSL-Ag is a specialized diosafety designation used for facilities handling pathogens that pose a risk to agricultural animals, plants, or ecosystems. Unlike standard BSLs, which focus on protecting human health, BSL-Ag is designed to prevent the spread of infectious agents that could devastate livestock, crops, or wildlife. Unlike ABSL, which has four levels, BSL-Ag does not prescribe to a tiered system. Instead, BSL-Ag facilities incorporate stringent containment measures tailored to the specific agricultural pathogens being studied. These measures often meet, or exceed, those of BSL-3 labs due to the economic and ecological consequences of an outbreak. BSL-Ag labs are characterized by the following features: Primary containment: Enclosures designed to prevent the escape of pathogens via air, water, or direct contact Secondary containment: Dedicated ventilation systems with HEPA filtration, airtight doors, and controlled airflows to prevent external contamination Personnel safety: Researchers are required to wear specialized PPE and follow strict decontamination procedures before exiting Environmental protection: Waste management and sterilization protocols ensure that no contaminated materials leave the facility What Are the Differences Between Biosafety Levels? Knowing the difference between biosafety levels and their corresponding safety requirements is imperative for anyone working with microbes in a lab setting; readers can use the chart below as a quick reference guide. Biosafety Level BSL-1 BSL-2 BSL-3 BSL-4 ABSL BSL-Ag Description – No containment – Defined Organisms – Unlikely to cause disease – Containment – Moderate Risk – Disease of varying severity – High Containment – Aerosol Transmission – Serious/Potentially lethal disease – Max Containment – “Exotic”, High-Risk Agents – Life-threatening disease – Aligns with the traditional BSL levels – Includes additional containment measures – Designation for facilities handling pathogens posing a risk to agricultural animals, plants, or ecosystems Sample Organisms Chicken pox, non-infectious types of bacteria, nonpathogenic strains of E. coli Dengue; equine encephalitis viruses; Hepatitis A, B, and C; HIV; lyme disease; measles; mumps; salmonella; Staphylococcus aureus Anthrax, COVID-19, hantavirus, malaria, Mycobacterium tuberculosis, Rift Valley fever, Rocky Mountain spotted fever, West Nile virus, Yellow fever Bolivian hemorrhagic fever (or other tropical hemorrhagic fevers), Ebola virus, Lassa fever, Marburg virus Adeno-associated virus, Staphylococcus aureus, Mycobacterium tuberculosis, Ebola virus Avian influenza virus, classical swine fever virus, eastern equine encephalitis virus, foot and mouth disease Pathogen Type Agents present minimal potential hazard to personnel and the environment Agents associated with human disease and post moderate hazards to personnel and the environment Indigenous or exotic agents, agents that present a potential for aerosol transmission, and agents causing serious or potentially lethal disease Dangerous and exotic agents that post a high risk of aerosol-transmitted laboratory infections and life-threatening disease ABSL-1 through ABSL-4 follow the same pathogen type pathway as BSL-1 through BSL-4 Designed to prevent the spread of infectious agents that could devastate livestock, crops, or wildlife Commonly Used Equipment Doesn’t require the use of specialized equipment. Research is typically conducted on benches Must include access to biological safety cabinets and decontamination equipment, such as incinerators and autoclaves Biological safety cabinets, incinerators, autoclaves, and a sustained directional airflow system must be present Must provide access to class III biosafety cabinets and be equipped with dedicated air supply and exhaust air (plus vacuum lines and decontamination systems) In addition to the equipment used in BSL labs, ABSL facilities regularly use animal restraint devices, cages, and cage washers Equipment used is similar in nature to that of BSL-3 and BSL-4 labs Autoclave Requirements None None Pass-thru autoclave with Bioseal required in laboratory room Pass-thru autoclave with bioseal required in laboratory room Autoclave requirements typically align with the corresponding BSL level Double-door autoclaves engineered with bioseals For additional biosafety level safety tips, we encourage you to download our free biosafety level checklist and microbe guide. Consolidated Sterilizer Systems also manufactures sterilizers for BSL-1, BSL-2, and BSL-3 laboratories — contact us today to learn more about any of our laboratory autoclaves. Biosafety Level Checklist & Common Microbe Guide Learn everything there is to know about biosafety level lab practices, safety procedures, facility construction requirements and more – including common microbes found at each level. Get The Guide Tweet Like Share
Biosafety Levels 1, 2, 3 & 4: What’s the Difference? Written by: Arthur Trapotsis MS Biochemical Engineering, MBA, Consultant Updated 11/3/22: Information about the biosafety level requirements for handling SAR-CoV-2 (COVID-19 coronavirus) can be found here. Safety is of the utmost importance in any laboratory setting, especially when working with autoclaving equipment. In order to ensure the safety of lab personnel, the environment and surrounding communities, the Centers for Disease Control and Prevention (CDC) have defined biosafety levels — each with corresponding safety protocols — for different types of facilities. In this blog post, we’ll explain what those biosafety levels are, how they’re defined, what precautionary measures lab workers need to take for each level, and more. What Are Biosafety Levels? Biological safety levels — often abbreviated to biosafety levels or BSL — are a series of protections specific to autoclave-related activities that take place in biological labs. Biosafety levels are individual safeguards designed to protect laboratory personnel, as well as the surrounding environment and community. Download our BSL Quick Reference Guide Here > These levels, which are ranked from one to four, are designated based on the biohazards (such as agents or organisms) laboratory personnel encounter in the lab. For example, a basic lab setting that specializes in the research of non-lethal agents that pose minimal threat to lab workers and the environment would generally be considered BSL-1, which is the lowest biosafety level. By way of comparison, a research laboratory that specializes in handling potentially deadly infectious agents, such as the Ebola virus, would be designated as a BSL-4 lab — the highest and most stringent biosafety level. It’s also important to keep in mind that while sometimes used interchangeably, biohazard levels are distinct from biosafety levels. To clarify, biohazard levels are used to classify agents based on the risk they pose to human life. BSLs, on the other hand, focus on the precautions that labs need to take to protect staff from these biohazards. This means that lab personnel can expect to encounter level one biohazards in a BSL-1 environment, level two biohazards in a BSL-2 setting, and so on. How Are Biosafety Levels Defined? The CDC sets biosafety levels to indicate what specific controls a laboratory must have in place for the containment of microbes and biological agents. Each biosafety level builds upon the previous level, thereby creating layer upon layer of constraints and barriers. Each biosafety level — BSL-1 through BSL-4 — is defined based on the following: Risks related to containment Severity of infection Transmissibility Nature of the work conducted within the lab Origin of the microbe Agent in question Route of exposure More specifically, when determining BSLs for different agents and microbes, the Centers for Disease Control and Prevention (CDC) recommends performing a biological risk assessment. This process involves taking the following steps to address agent and protocol risks: Identify the agent’s hazardous characteristics: Assess the agent’s ability to cause disease, severity, transmission routes, infectious dose, stability, and host range. Identify laboratory procedure hazards: Determine the risks presented by handling techniques; equipment use; aerosol generation; and exposure routes such as skin contact, ingestion, inhalation, and needle sticks. Determine the appropriate BSL: Select the necessary BSL based on risk assessment, factoring in safety precautions, facility safeguards, and regulatory requirements. This determination is typically made by a group that includes a principal investigator, institutional biosafety professionals, and biosafety committees. Biosafety levels dictate the types of work practices allowed to take place in a lab setting; they also heavily influence the overall design of a facility and the type of specialized safety equipment in it. Get Your Safety Tips Checklist for BSL Labs 1–4 Here > Biosafety Level 1 (BSL-1) The lowest of the four biosafety levels, biosafety level 1 (BSL-1) applies to laboratory settings in which personnel work with low-risk microbes that pose little to no threat of infection in healthy adults. Because of this, BSL-1 labs typically do not need to be isolated from surrounding facilities. Types of Agents Studied Some examples of the microbes handled in biosafety level-1 labs include: Chicken pox Non-infectious types of bacteria Nonpathogenic strains of E. coli Commonly Used Equipment As the lowest biosafety level, BSL-1 labs don’t require the use of specialized equipment to carry out research, which is typically conducted on benches. Surfaces should be easy to clean and able to tolerate standard laboratory chemicals. Safety Protocols Safety protocols for biosafety level 1 labs — which require only basic microbial practices — include: Mechanical pipetting (no mouth pipetting allowed) Safe sharps handling Avoidance of splashes or aerosols Daily decontamination of all work surfaces when work is complete Regular handwashing Prohibition of food, drink, and smoking materials The use of personal protective equipment (PPE), such as goggles, gloves, and a lab coat or gown Biohazard signs BSL-1 labs also require immediate decontamination after spills. Infectious materials should also be decontaminated prior to disposal, generally through the use of an autoclave. Biosafety Level 2 (BSL-2) Biosafety level 2 (BSL-2) covers all laboratories that work with agents associated with human diseases — that is, pathogenic or infectious organisms — that pose a moderate health hazard if inhaled, ingested, or exposed to the skin. BSL-2 labs must follow the same standard microbial practices as BSL-1 labs while also implementing additional precautions to address the higher risk associated with the agents they study. Personnel working in biosafety level 2 laboratories are expected to take even greater care to prevent injuries, such as cuts and other breakage to the skin, as well as ingestion and mucous membrane exposures. Types of Agents Studied BSL-2 labs might study the following: Dengue Equine encephalitis viruses Hepatitis A, B, and C HIV Lyme disease Measles Mumps Salmonella Staphylococcus aureus (staph infections) Commonly Used Equipment Given the nature of the agents present in BSL-2 labs, workspaces must have access to equipment capable of decontaminating waste, such as incinerators and autoclaves (or another decontamination method). Additionally, all procedures that could cause infection from aerosols or splashes must be performed within a biological safety cabinet. Safety Protocols In addition to the safety protocols established for BSL-1 labs, BSL-2 labs are subject to the following safety controls: The use of PPE, including lab coats, gloves, eye protection, and — in some cases — face shields Decontamination of infectious materials prior to disposal, generally through the use of an autoclave Self-closing, lockable doors Access to a sink and eyewash station Biohazard warning signs Access to a biosafety level 2 lab is far more restrictive than to a biosafety level 1 lab. Outside personnel, or those with an increased risk of contamination, are often restricted from entering the area while work is underway. Get our BSL Quick Reference & Safety Tips Guide Here > Biosafety Level 3 (BSL-3) Once again building on the two prior biosafety levels, a biosafety level 3 (BSL-3) laboratory typically conducts research into or work on microbes that are either indigenous or exotic and can cause serious or potentially lethal disease through inhalation. Types of Agents Studied Common examples of microbes found in BSL-3 labs include: Anthrax COVID-19 Hantavirus Malaria Mycobacterium tuberculosis Rift Valley fever Rocky Mountain spotted fever West Nile virus Yellow fever Commonly Used Equipment To ensure the safety of laboratory staff, biosafety cabinets, incinerators, autoclaves, and a sustained directional airflow system — to draw air into the laboratory from clean, non-laboratory areas toward potentially contaminated areas — must be present. Safety Protocols Microbes found within biosafety level 3 settings are so serious that work is often strictly controlled and registered through the appropriate government agencies. Laboratory personnel are also under medical surveillance and may require immunizations for the microbes they work with. Common safety controls within a BSL-3 lab include: The use of PPE, including goggles and gloves; respirators may also be required The use of solid-front wraparound gowns, scrub suits, and/or coveralls is often required Access to a hands-free sink and eyewash station available near the exit Self-closing set of locking doors with access away from general building corridors Access to a BSL-3 laboratory is restricted and controlled at all times. Biosafety Level 4 (BSL-4) Biosafety level 4 (BSL-4) labs are rare; however, a small number exist in the U.S. and around the world. As the highest level of biological safety, BSL-4 labs work with highly dangerous and exotic microbes. Infections caused by these types of microbes are often fatal and come without treatment or vaccines. Types of Agents Studied Agents present in BSL-4 labs might include: Bolivian hemorrhagic fever (or other tropical hemorrhagic fevers) Ebola virus Lassa fever Marburg virus Commonly Used Equipment Since biosafety level 4 labs deal with the most dangerous agents, they are required to house advanced equipment that enables researchers to safely carry out their studies. All BSL-4 environments must provide access to class III biosafety cabinets and be equipped with dedicated air supply and exhaust air (plus vacuum lines and decontamination systems). Safety Protocols In addition to biosafety level 3 considerations, biosafety level 4 laboratories must follow these safety protocols: Personnel must change clothing before entering the facility and shower upon exiting All materials must be decontaminated before leaving the facility Personnel must wear the PPE from lower BSL levels, as well as a full-body, air-supplied, positive pressure suit BSL-4 labs are extremely isolated, often located in an isolated and restricted zone of a building or in a separate building entirely. BSL-4 labs also feature a dedicated supply of exhaust air, as well as vacuum lines and decontamination systems. Get our BSL Quick Reference & Safety Tips Guide Here > Additional Biosafety Levels In addition to the biosafety levels previously discussed, specialized biosafety classifications exist for certain types of research. Two key examples are Animal Biosafety Levels (ABSL) and Agricultural Biosafety Levels (BSL-Ag), which are designed to address the unique risks associated with animal and agricultural research. Animal Biosafety Levels ABSL classifications are used in research involving animals that carry or are infected with potentially hazardous biological agents. These levels — ABSL-1 through ABSL-4 — align with traditional BSLs, but include additional containment measures to protect researchers, prevent cross-contamination, and ensure animal welfare. ABSL-1: Used for research involving animals that carry well-characterized agents that aren’t known to cause disease in humans. ABSL-2: Research involves animals infected with agents that pose moderate health hazards to humans, such as certain viruses, bacteria, and parasites. ABSL-3: Labs work with animals infected with agents that can cause serious or potentially lethal disease in humans as well as agents that spread through aerosol transmission, such as Mycobacterium tuberculosis. ABSL-4: Denotes a laboratory environment where researchers work with animals infected with highly dangerous pathogens that cause life-threatening disease, pose a high risk of aerosol transmission, or have an unknown transmission risk. Agricultural Biosafety Levels BSL-Ag is a specialized diosafety designation used for facilities handling pathogens that pose a risk to agricultural animals, plants, or ecosystems. Unlike standard BSLs, which focus on protecting human health, BSL-Ag is designed to prevent the spread of infectious agents that could devastate livestock, crops, or wildlife. Unlike ABSL, which has four levels, BSL-Ag does not prescribe to a tiered system. Instead, BSL-Ag facilities incorporate stringent containment measures tailored to the specific agricultural pathogens being studied. These measures often meet, or exceed, those of BSL-3 labs due to the economic and ecological consequences of an outbreak. BSL-Ag labs are characterized by the following features: Primary containment: Enclosures designed to prevent the escape of pathogens via air, water, or direct contact Secondary containment: Dedicated ventilation systems with HEPA filtration, airtight doors, and controlled airflows to prevent external contamination Personnel safety: Researchers are required to wear specialized PPE and follow strict decontamination procedures before exiting Environmental protection: Waste management and sterilization protocols ensure that no contaminated materials leave the facility What Are the Differences Between Biosafety Levels? Knowing the difference between biosafety levels and their corresponding safety requirements is imperative for anyone working with microbes in a lab setting; readers can use the chart below as a quick reference guide. Biosafety Level BSL-1 BSL-2 BSL-3 BSL-4 ABSL BSL-Ag Description – No containment – Defined Organisms – Unlikely to cause disease – Containment – Moderate Risk – Disease of varying severity – High Containment – Aerosol Transmission – Serious/Potentially lethal disease – Max Containment – “Exotic”, High-Risk Agents – Life-threatening disease – Aligns with the traditional BSL levels – Includes additional containment measures – Designation for facilities handling pathogens posing a risk to agricultural animals, plants, or ecosystems Sample Organisms Chicken pox, non-infectious types of bacteria, nonpathogenic strains of E. coli Dengue; equine encephalitis viruses; Hepatitis A, B, and C; HIV; lyme disease; measles; mumps; salmonella; Staphylococcus aureus Anthrax, COVID-19, hantavirus, malaria, Mycobacterium tuberculosis, Rift Valley fever, Rocky Mountain spotted fever, West Nile virus, Yellow fever Bolivian hemorrhagic fever (or other tropical hemorrhagic fevers), Ebola virus, Lassa fever, Marburg virus Adeno-associated virus, Staphylococcus aureus, Mycobacterium tuberculosis, Ebola virus Avian influenza virus, classical swine fever virus, eastern equine encephalitis virus, foot and mouth disease Pathogen Type Agents present minimal potential hazard to personnel and the environment Agents associated with human disease and post moderate hazards to personnel and the environment Indigenous or exotic agents, agents that present a potential for aerosol transmission, and agents causing serious or potentially lethal disease Dangerous and exotic agents that post a high risk of aerosol-transmitted laboratory infections and life-threatening disease ABSL-1 through ABSL-4 follow the same pathogen type pathway as BSL-1 through BSL-4 Designed to prevent the spread of infectious agents that could devastate livestock, crops, or wildlife Commonly Used Equipment Doesn’t require the use of specialized equipment. Research is typically conducted on benches Must include access to biological safety cabinets and decontamination equipment, such as incinerators and autoclaves Biological safety cabinets, incinerators, autoclaves, and a sustained directional airflow system must be present Must provide access to class III biosafety cabinets and be equipped with dedicated air supply and exhaust air (plus vacuum lines and decontamination systems) In addition to the equipment used in BSL labs, ABSL facilities regularly use animal restraint devices, cages, and cage washers Equipment used is similar in nature to that of BSL-3 and BSL-4 labs Autoclave Requirements None None Pass-thru autoclave with Bioseal required in laboratory room Pass-thru autoclave with bioseal required in laboratory room Autoclave requirements typically align with the corresponding BSL level Double-door autoclaves engineered with bioseals For additional biosafety level safety tips, we encourage you to download our free biosafety level checklist and microbe guide. Consolidated Sterilizer Systems also manufactures sterilizers for BSL-1, BSL-2, and BSL-3 laboratories — contact us today to learn more about any of our laboratory autoclaves. Biosafety Level Checklist & Common Microbe Guide Learn everything there is to know about biosafety level lab practices, safety procedures, facility construction requirements and more – including common microbes found at each level. Get The Guide Tweet Like Share
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