Biosafety Levels 1, 2, 3 & 4 | What's The Difference? (2022)

Biosafety Levels 1, 2, 3 & 4 | What's The Difference? (2)

Written by: Arthur Trapotsis

Updated 3/31/20: Information about the biosafety level requirements for handling SAR-CoV-2 (COVID-19 coronavirus) can be found here.

Biological Safety Levels (BSL) are a series of protections relegated to autoclave-related activities that take place in particular biological labs. They are individual safeguards designed to protect laboratory personnel, as well as the surrounding environment and community.

These levels, which are ranked from one to four, are selected based on the agents or organisms that are being researched or worked on in any given laboratory setting. For example, a basic lab setting specializing in the research of nonlethal agents that pose a minimal potential threat to lab workers and the environment are generally considered BSL-1—the lowest biosafety lab level. A specialized research laboratory that deals with potentially deadly infectious agents like Ebola would be designated as BSL-4—the highest and most stringent level.

(Video) Understanding Biosafety Levels

The Centers for Disease Control and Prevention (CDC) sets BSL lab levels as a way of exhibiting specific controls for the containment of microbes and biological agents. Each BSL lab level builds upon on the previous level—thereby creating layer upon layer of constraints and barriers. These lab levels are determined by the following

  • Risks related to containment
  • Severity of infection
  • Transmissibility
  • Nature of the work conducted
  • Origin of the microbe
  • Agent in question
  • Route of exposure

The reason biosafety levels are so important is because they dictate the type of work practices that are allowed to take place in a lab setting. They also heavily influence the overall design of the facility in question, as well as the type of specialized safety equipment used within it.

The following is an explanation of each biosafety level—what they mean and how they differ in safety measures and best practices.

Download our BSL Quick Reference Guide Here >

BSL–1

As the lowest of the four, biosafety level 1 applies to laboratory settings in which personnel work with low-risk microbes that pose little to no threat of infection in healthy adults. An example of a microbe that is typically worked with at a BSL-1 is a nonpathogenic strain of E. coli.

This laboratory setting typically consists of research taking place on benches without the use of special contaminant equipment. A BSL-1 lab, which is not required to be isolated from surrounding facilities, houses activities that require only standard microbial practices, such as:

  • Mechanical pipetting only (no mouth pipetting allowed)
  • Safe sharps handling
  • Avoidance of splashes or aerosols
  • Daily decontamination of all work surfaces when work is complete
  • Hand washing
  • Prohibition of food, drink and smoking materials in lab setting
  • Personal protective equipment, such as; eye protection, gloves and a lab coat or gown
  • Biohazard signs

BSL-1 labs also requires immediate decontamination after spills. Infection materials are also decontaminated prior to disposal, generally through the use of an autoclave.

BSL–2

This biosafety level covers laboratories that work with agents associated with human diseases (i.e. pathogenic or infections organisms) that pose a moderate health hazard. Examples of agents typically worked with in a BSL-2 include equine encephalitis viruses and HIV, as well as Staphylococcus aureus (staph infections).

BSL-2 laboratories maintain the same standard microbial practices as BSL-1 labs, but also includes enhanced measures due to the potential risk of the aforementioned microbes. Personnel working in BSL-2 labs are expected to take even greater care to prevent injuries such as cuts and other breaches of the skin, as well as ingestion and mucous membrane exposures.

(Video) What are the different biosafety levels (BSL) in a lab - CytoSMART Academy

In addition to BSL 1 expectation, the following practices are required in a BSL 2 lab setting:

  • Appropriate personal protective equipment (PPE) must be worn, including lab coats and gloves. Eye protection and face shields can also be worn, as needed.
  • All procedures that can cause infection from aerosols or splashes are performed within a biological safety cabinet (BSC).
  • An autoclave or an alternative method of decontamination is available for proper disposals.
  • The laboratory has self-closing, lockable doors.
  • A sink and eyewash station should be readily available.
  • Biohazard warning signs

Access to a BSL-2 lab is far more restrictive than a BSL-1 lab. Outside personnel, or those with an increased risk of contamination, are often restricted from entering when work is being conducted.

BSL-3

Again building upon the two prior biosafety levels, a BSL-3 laboratory typically includes work on microbes that are either indigenous or exotic, and can cause serious or potentially lethal disease through inhalation. Examples of microbes worked with in a BSL-3 includes; yellow fever, West Nile virus, and the bacteria that causes tuberculosis.

The microbes are so serious that the work is often strictly controlled and registered with the appropriate government agencies. Laboratory personnel are also under medical surveillance and could receive immunizations for microbes they work with.

Common requirements in a BSL-3 laboratory include:

  • Standard personal protective equipment must be worn, and respirators might be required
  • Solid-front wraparound gowns, scrub suits or coveralls are often required
  • All work with microbes must be performed within an appropriate BSC
  • Access hands-free sink and eyewash are available near the exit
  • Sustained directional airflow to draw air into the laboratory from clean areas towards potentially contaminated areas (Exhaust air cannot be re-circulated)
  • A 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.

BSL-4

BSL-4 labs are rare. However some do exist in a small number of places in the US and around the world. As the highest level of biological safety, a BSL-4 lab consists of work with highly dangerous and exotic microbes. Infections caused by these types of microbes are frequently fatal, and come without treatment or vaccines. Two examples of such microbes include Ebola and Marburgviruses.

In addition to BSL-3 considerations, BSL-4 laboratories have the following containment requirements:

(Video) What are the four Biosafety Levels (BSL)?

  • Personnel are required to change clothing before entering, shower upon exiting
  • Decontamination of all materials before exiting
  • Personnel must wear appropriate personal protective equipment from prior BSL levels, as well as a full body, air-supplied, positive pressure suit
  • A Class III biological safety cabinet

A BSL-4 laboratory is extremely isolated—often located in a separate building or in an isolated and restricted zone of the building. The laboratory also features a dedicated supply and exhaust air, as well as vacuum lines and decontamination systems.

Knowing the difference in biosafety lab levels and their corresponding safety requirements is imperative for anyone working with microbes in a lab setting.

Get Your Safety Tips Checklist for BSL Labs 1-4 Here >

Information about the biosafety level requirements for handling SAR-CoV-2 (COVID-19 coronavirus) can be found here.

Biosafety Levels 1, 2, 3 & 4 | What's The Difference? (3)

Consolidated Sterilizer Systems produces sterilizers for BSL-1, BSL-2, and BSL-3 laboratories.

Biosafety Levels 1, 2, 3 & 4 | What's The Difference? (4)

(Video) Difference between BIOSAFETY LEVELS | Biosafety levels 1,2,3 & 4.

Arthur Trapotsis

Arthur has over 20 years of experience in the sterilizer industry and possesses a background in biotechnology, chemical engineering, and business management. He regularly presents at conferences around the country about eco-friendly autoclave design features, as well as emerging trends in the steam sterilizer market. Arthur graduated from Tufts University with a B.S. and M.S. in Biochemical Engineering and earned an M.B.A. in Entrepreneurship from Babson College. Although he dedicates much of his focus to driving the needle of autoclave innovation forward, Arthur is also a strong advocate for leading a balanced lifestyle of work, family and fitness — an outlook he shares with all of his employees.

Biosafety Levels 1, 2, 3 & 4 | What's The Difference? (5)

17 Questions to Ask Before Buying Your Next Autoclave

With so many models, sizes, options and components to choose from, how can you ever really know exactly what you need to make the most out of your investment?

These questions will help you to make informed decisions by outlining what is most important to consider and know about owning an autoclave.

(Video) BioSafety Level Labs: BSL 1 vs BSL 2 vs BSL 3 vs BSL 4 | Hindi | Priyank Singhvi

FAQs

What is the difference between biosafety level 1 and 2? ›

All activities in a BSL-2 laboratory require higher security standards than in a BSL-1 laboratory. The biological material used in a BSL-2 laboratory consists of bacteria, viruses, and organisms associated with human diseases.

What are the 4 biosafety 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.

What is the meaning of biosafety level 1? ›

BSL-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 is a biosafety level 3? ›

Biosafety Level 3 (BSL-3)​

BSL-3 laboratories are used to study infectious agents or toxins that may be transmitted through the air and cause potentially lethal infections. Researchers perform all experiments in a biosafety cabinet. BSL-3 laboratories are designed to be easily decontaminated.

What is a level 4 agent? ›

Level 4. Agents requiring BSL 4 facilities and practices are extremely dangerous and pose a high risk of life-threatening disease. Examples are the Ebola virus, the Lassa virus, and any agent with unknown risks of pathogenicity and transmission. These facilities provide the maximum protection and containment.

How many BSL-4 labs are there? ›

There are currently only four operational BSL-4 laboratory suites in the United States: at the Centers for Disease Control and Prevention in Atlanta; at the United States Army Medical Research Institute for Infectious Diseases at Fort Detrick in Frederick, Maryland; at the Southwest Foundation for Biomedical Research ...

What Biosafety Level is E coli? ›

BIOSAFETY LEVEL 2

(CDC) 21-1112) from the U.S. Department of Health and Human Services, Centers for Disease Control and Prevention and National Institutes of Health.

What are BSL 3 organisms list? ›

NIAID BSL-3 Priority Pathogens
  • Anthrax (Bacillus anthracis) ...
  • Brucella (Brucella abortus) ...
  • Burkholderia. ...
  • Botulism (Clostridium botulinum) ...
  • Tularemia (Francisella tularensis) ...
  • Tuberculosis (Mycobacterium tuberculosis) ...
  • Plague (Yersinia pestis) ...
  • Q FEVER (Coxiella burnetii)

What biosafety level is Ebola? ›

BIOSAFETY LEVEL 4 (BSL-4) LABS

Work with the world's most deadly agents, including viruses that cause smallpox and viral hemorrhagic fevers, such as Ebola, is done at biosafety level 4 (BSL-4).

What are the Level 4 viruses? ›

Biohazard Level 4 usually includes dangerous viruses like Ebola, Marburg virus, Lassa fever, Bolivian hemorrhagic fever, and many other hemorrhagic viruses found in the tropics.

What are the essential requirements of BSL 3? ›

  • Prerequisites for the construction of BSL-3/ Assessment of proposed facility.
  • Establishment of basic objectives. Predesign.
  • Design. Construction.
  • Commissioning. Validation.
  • Operation and. maintenance.

What are BSL 1 agents? ›

Definitions. Risk Group 1 (RG1) agents are not associated with disease in healthy adult humans. Biosafety Level 1 (BSL-1) is suitable for work involving well-characterized agents not known to cause disease in healthy adult humans, and of minimal potential hazard to laboratory personnel and the environment.

What is a Category 3 pathogen? ›

WHO Risk Group 3 (high individual risk, low community risk) - A pathogen that usually causes serious human or animal disease but does not ordinarily spread from one infected individual to another. Effective treatment and preventive measures are available.

What is a P3 laboratory? ›

A P3 laboratory is a containment facility that enables the isolation and manipulation of dangerous biological materials for various research purposes. P3 laboratories are subjected to BSL-3 standards, which permit the handling of biological agents that can be transmitted through aerosols.

What is contaminant level1? ›

Containment level 1 (CL 1) is used for work with low risk biological agents and hazards, genetically modified organisms, animals and plants.

What are risk group 4 organisms examples? ›

Risk Group 4 (RG4)

Pathogen Risk Group 4 poses a high risk to individuals and the environment; microorganisms that cause life-threatening disease, readily spread, and where treatment is usually not available. Common examples of RG4 pathogens include Ebola and Hendra virus.

What diseases are studied in a BSL-4 lab? ›

Biosafety level 4 laboratories are used for diagnostic work and research on easily transmitted pathogens which can cause fatal disease. These include a number of viruses known to cause viral hemorrhagic fever such as Marburg virus, Ebola virus, Lassa virus, and Crimean-Congo hemorrhagic fever.

What is Level 4 hot zone? ›

The Biosafety Level 4 rooms contain BL-4 agents, also known as hot agents. A BL-4 hot agent is a lethal virus for which, in most cases, there is no vaccine and no cure. It is in the nature of hot agents to travel through the air: they can become airborne.

What are the requirements for a BSL 2 lab? ›

In a BSL-2 lab, the following conditions are to exist:
  • Doors. Doors that can be locked and secured should be installed for facilities that house restricted areas.
  • Public. ...
  • Sink. ...
  • Cleaning. ...
  • Bench Tops. ...
  • Lab Furniture. ...
  • Biological Safety Cabinets. ...
  • Eyewash Station.

How many biosafety levels are there? ›

There are four biosafety levels (BSLs) that define proper laboratory techniques, safety equipment, and design, depending on the types of agents being studied: BSL-1 labs are used to study agents not known to consistently cause disease in healthy adults.

What is the purpose of biosafety? ›

Biosafety is a framework that describes the use of specific practices, training, safety equipment, and specially designed buildings to protect the worker, community, and environment from an accidental exposure or unintentional release of infectious agents and toxins.

What BSL level is anthrax? ›

anthracis), under biosafety level (BSL) 3 containment conditions.

Which biosafety level does Salmonella belong? ›

Summary
Agent TypeRisk GroupAnimal Housing Biosafety Level
BacteriaRG-2ABSL-2

Is E. coli a BSL 2 organism? ›

Organisms. The organisms that require BSL-2 laboratories include the pathogenic strains of E. coli, Staphylococcus, Salmonella, Plasmodium falciparum, Toxoplasma, and Herpes Simples Viruses.

What is a BSL 2 Hood? ›

Class II Type A2 Biological Safety Cabinet / Tissue Culture Hood (Biosafety Cabinet) A class II biological safety cabinet is a partially enclosed workspace that has built in protection for the worker, the environment, and the material inside of it.

What is one example of an organism that would require BSL 1? ›

The agents require Biosafety Level 1 containment. Examples of BSL-1 organisms are: Agrobacterium radiobacter, Aspergillus niger, Bacillus thuringiensis, Escherichia coli strain K12, Lactobacillus acidophilus, Micrococcus leuteus, Neurospora crassa, Pseudomonas fluorescens, Serratia marcescens.

Are prions a biohazard? ›

Prions & General Biosafety Recommendations

All other animal prions are considered BSL-2 pathogens. However, when a prion from one species is inoculated into another the resultant infected animal should be treated according to the guidelines applying to the source of the inoculum.

Which class of biosafety cabinets provides the most protection? ›

Class III Biosafety Cabinets – Total Containment Cabinets

Class III biological safety cabinets are gas-tight, designed for use with high risk biological agents. Class III cabinets provide the highest level of personnel, product and environmental protection.

Why is it important that a negative air pressure is maintained inside the Biosafety Level 3 lab? ›

Preventing spread of BSL III pathogens is crucial. When a spill or accident occurs the negative pressure in the biosafety level III laboratory room prevents that these pathogens leave the laboratory room.

Is smallpox Biosafety Level 4? ›

Biosafety Level 4 criteria are used when working with smallpox. Smallpox is very contagious and easily spread from person to person. Always use appropriate personal protective equipment including masks, laboratory coats, gloves, and eye or face shields when collecting and handling specimens.

How many levels of diseases are there? ›

There are four main types of disease: infectious diseases, deficiency diseases, hereditary diseases (including both genetic diseases and non-genetic hereditary diseases), and physiological diseases.

What type of virus is Ebola? ›

About Ebola Virus Disease

Ebola is caused by infection with a virus of the family Filoviridae , genus Ebolavirus.

How many exit door should be in the lab? ›

important not to place obstructions near them so personnel can quickly exit in an emergency. Even in modular labs where there may be more than one door, a good policy is to ensure that at least two exits are readily accessible and not blocked.

How much does it cost to build a BSL 3 lab? ›

This US$2 million project involved converting an existing laboratory space into a BSL-3 suite for faculty research programmes.

Does BSL-1 need biosafety cabinet? ›

Biosafety Level 1 (BSL-1)

Lab personnel are handling specimens with little risk of infecting healthy human beings. One example of a microbe with a level 1 rating (BSL-1) is E. coli. While handling BSL-1 specimens, the lab doesn't need any advanced containment equipment.

What is a BSL 2 Hood? ›

Class II Type A2 Biological Safety Cabinet / Tissue Culture Hood (Biosafety Cabinet) A class II biological safety cabinet is a partially enclosed workspace that has built in protection for the worker, the environment, and the material inside of it.

What is a containment level 2 laboratory? ›

Containment level 2 (CL 2) is used for work with medium risk biological agents and hazards, genetically modified organisms, animals and plants.

What is contaminant level1? ›

Containment level 1 (CL 1) is used for work with low risk biological agents and hazards, genetically modified organisms, animals and plants.

What BSL is E. coli? ›

Follow requirements and practices for your assigned BSL:
Biosafety levels (BSL)BSL–1
1. Degree of hazardLow risk: Well characterized agents not known to cause disease in healthy adult humans
2. ExamplesEscherichia coli (laboratory strain)
B. Standard microbiological practices
Biosafety levels (BSL)BSL–1
34 more rows
13 Sept 2022

Is E. coli a BSL-2 organism? ›

Organisms. The organisms that require BSL-2 laboratories include the pathogenic strains of E. coli, Staphylococcus, Salmonella, Plasmodium falciparum, Toxoplasma, and Herpes Simples Viruses.

What biosafety level is Salmonella? ›

A comprehensive set of biosafety guidelines for work with Salmonella and other similar human pathogens can be found in the Biosafety Level 2 section of the CDC/NIH Biosafety in Microbiological and Biomedical Laboratories manual, the Guidelines for Safe Work Practices in Human and Animal Medical Diagnostic Laboratories ...

What is the primary difference between the Class II type A1 A2 and B1 B2 cabinets? ›

NSF defines four types of Class II cabinets (A1, A2, B1 and B2) that are distinguished by differences in airflow patterns and velocities, HEPA air filter positions, ventilation rates and exhaust methods.

What is a Class 1 biological safety cabinet? ›

The Class 1 biological safety cabinet provides personnel and environment protection for the safe handling when working with chemicals and powders. The air enters the cabinet via the front aperture passing through a built-in exhaust fan, HEPA and/or Carbon filter, thus providing operator and environmental protection.

What does a Level 2 biosafety cabinet protect? ›

Class 2. Class 2 biological safety cabinets protect people, the environment, and work samples. These biosafety cabinets are divided into four subtypes—A1, A2, B1, and B2–depending on their airflow speeds and exhaust systems.

What is a Category 1 laboratory? ›

BSL–1. As the lowest of the four, biosafety level 1 applies to laboratory settings in which personnel work with low-risk microbes that pose little to no threat of infection in healthy adults. An example of a microbe that is typically worked with at a BSL-1 is a nonpathogenic strain of E. coli.

What is a Category 3 laboratory? ›

Containment level 3 (CL 3) is used for work with high risk biological agents and hazards, genetically modified organisms, animals and plants.

What are BSL 3 organisms list? ›

NIAID BSL-3 Priority Pathogens
  • Anthrax (Bacillus anthracis) ...
  • Brucella (Brucella abortus) ...
  • Burkholderia. ...
  • Botulism (Clostridium botulinum) ...
  • Tularemia (Francisella tularensis) ...
  • Tuberculosis (Mycobacterium tuberculosis) ...
  • Plague (Yersinia pestis) ...
  • Q FEVER (Coxiella burnetii)

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