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What is BSL3?

Biosafety Level 3 (BSL3) is one of 4 biosafety level classifications designated by the Center for Disease Control and Prevention. Risk Group 3 includes "indigenous or exotic agents which may cause serious or potentially lethal disease as a result of exposure by the inhalation route". Effective treatment or prophylaxis is usually available. To ensure safety of the researchers and the local community, personnel working in the BSL3 facilities are required to complete a rigorous training program and use specific BSL3 procedures that prevent the release of agents outside of the primary work space (i.e. the biosafety cabinet). In parallel, the BSL3 facilities are designed to prevent the release of hazardous agents into the environment.

What are the Biosafety Level classifications?

Classification of risk group and biosafety levels are defined differently worldwide. The laboratory biosafety levels in the US are based on the Center of Disease Control and Prevention (CDC) classifications which group biological research into categories 1 through 4. These categories are based on the increasing level of risk that microbial pathogens can present to humans and animals. Criteria for biological containment levels can be found in the CDC publication "Biosafety in Microbiological and Biomedical Laboratories (BMBL)".

Biosafety Level 1 includes pathogens that present low or no risk of infection to healthy humans/animals while people infected by pathogens assigned to Biosafety Level 4 suffer a high mortality rate. Research in BSL3 laboratories involves Risk Group 3 agents such as Mycobacterium tuberculosis or Francisella tularensis which can cause serious and potentially lethal human and/or animal diseases, and also presents an occupational health hazard. Risk group 3 agents are treatable. The American Biological Safety Association (ABSA) provides a database with details on the biosafety levels of most organisms used in research. The BSL3 designation applies to specific facility design, in addition to safety equipment and work practices that must be strictly followed. The facilities use sophisticated engineering controls, including directional air flow and air pressure differentials, to contain hazardous agents within the work space. Users of the facility are required to complete a comprehensive training process before facility access can be granted. The lab is designed not only to prevent exposure of research personnel to the pathogens but also to avoid releasing hazardous agents into the environment. The general guidelines for a BSL3 facility are summarized in the table below:

BSL Agents Practices Primary Barriers and Safety Equipments Facilities
(Secondary Barriers)
3 Indigenous or exotic agents with potential for aerosol transmission

Disease may have serious or lethal consequences
Baseline serum
Standard Microbiological Practices

Controlled access

Biohazard warning signs

“sharp” precautions

Biosafety manual defining any needed waste decontamination or medical surveillance policies

Decontamination of all waste

Decontamination of laboratory clothing before laundering
Protective laboratory clothing; gloves; respiratory protection as needed
Primary barriers:
Class I or II BSCs or other physical containment devices used for all open manipulation of agents

protective lab clothing; gloves; respiratory protection as needed
Negative airflow into laboratory
Laboratory bench and sink required

Autoclave available

Physical separation from access corridor

Self-closing, double-door access

Exhaust air not recirculated


General BSL3 criteria (Biosafety in Microbiological and Biomedical Laboratories (BMBL) 5th Edition (Sect. IV, Table I))

How many BSL3 facilities are present in the US?

According to the United State Government Accountability Office (GAO) report published on October 4, 2007, a total of 1356 CDC/USDA registered BSL3 facilities were identified throughout the United States (GAO-08-108T). 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. This number includes 2 National Biocontainment Laboratories (NBL) and 11 Regional Biocontainment Laboratories (RBL) with BSL3 and/or BSL-4 capabilities that are funded by NIAID.

Why do we need BSL3 at OSU?

OSU is committed to performing research on infectious diseases that have both local and global impact, with an overarching goal to improve human health. The study of many infectious diseases that have impact on human health requires specific safety precautions that BSL3 facilities provide.

BSL3 facilities at OSU provide the necessary infrastructure to ensure that researchers can perform the most relevant working models and systems to investigate risk group 3 organisms, increases our national and international reputation, allow collaboration opportunities with government and private sectors in conducting translational research projects, and generate competitive research funding.

Why is BSL3 safe and secure?

The safe operation of BSL3 facilities relies upon an integrated program that includes the practices and operations described below.

1) Facilities design and operation
The BSL3 facilities are constructed following regulations set by state and federal regulations, NIH and CDC. The engineering of the facility follows stringent specifications to maintain air pressure balance control. In addition, several automatic monitoring and notification systems are built into the system to ensure maximum safety for research personnel. The design and operation of the facility is certified by 3rd party professionals annually. Service personnel perform monthly preventative maintenance on the systems and equipment of each facility. Besides airflow monitoring, additional safety and security features include:

  • HEPA filtration of all air exiting the facility
  • Type II biosafety cabinets where infectious work is conducted
  • Pass-through autoclave for decontamination of all waste before disposal
  • Hands free sink, eyewash station, shower, and other safety equipment
  • Restricted access with security monitoring

2) Specialized BSL3 Equipment
BSL3 facilities contain specialized equipment that reduces the possibility of aerosol generation. These include the use of class II biosafety cabinets (BSC), centrifuges that utilize aerosol containment buckets, equipment with HEPA filtration, and the placement of aerosol generating equipment within the BSC.

3) Personal protective equipment (PPE)
Each individual working in BSL3 is required to wear protective equipment. The PPE includes a wrap around water resistant gown, eye protection, hairnet and shoe cover, two layers of gloves, and an N-95 mask. All PPE are single use and are safely removed according to specific protocols before users leave the facility.

4) Decontamination
All equipment and waste are decontaminated prior to leaving the facility.

Waste and PPE are autoclaved prior to final disposal. Autoclaving applies a high temperature and pressure that is sufficient to kill microorganisms. The effectiveness of the decontamination process is validated through both chemical and biological indicators. Final disposal of autoclaved waste is by incineration.

Equipment, samples, and other items that cannot be autoclaved are decontaminated using approved and validated decontamination protocols. All protocols are validated for effective decontamination using virulent BSL3 pathogens at concentrations greater that those routinely used for experimentation. Decontamination protocols are reviewed and approved by the BSL3 operations group prior to use.

5) Operator training and work practices
All BSL3 protocols, and amended protocols, are reviewed by the Institutional Biosafety Committee (IBC) to verify that BSL3 work practices and appropriate safety precautions have been addressed. The BSL3 Program leaders assist principal investigators with the development of safe and effective BSL3 protocols.

Each new BSL3 researcher must complete a comprehensive training program prior to working in the BSL3 facility. Users are provided with out-of-facility training and information that includes discussions of specific BSL3 work practices, emergency response, and details of the facilities. Users are required to enroll in an occupational health plan prior to BSL3 entry. Users are subsequently provided with in-facility training by experienced BSL3 Program approved trainers who provide hands on training in general BSL3 work practices and investigator specific procedures.

BSL3 practices include the use of specific containment techniques whereby all procedures with live BSL3 agents are performed within primary containment (biosafety cabinet) using specific handling procedures that minimize air movement. All agents are secured prior to movement within the laboratory, and all waste is decontaminated using approved procedures.

Users are required to attend a monthly BSL3 users group where new information is disseminated, protocols are discussed, and users frequently participate in pop-quizzes to maintain an up to date knowledge of BSL3 practices. BSL3 users are also required to attend an annual refresher training which includes emergency response drills and hands-on procedures to ensure that users maintain the high level of BSL3 safety practices that are required for safe and effective BSL3 operations.

What kind of work is done in OSU BSL3 facilities?

Research in the facilities focuses on the study of immune response to pathogens, pathogen interactions with host cells, molecular and biochemical analysis of pathogens, and vaccine studies. All of the research projects performed at OSU aim to generate information that will improve human (and animal) health. No bio-weapon research is performed in BSL3 facilities at the Ohio State University.

Is there an emergency response?

The OSU BSL3 program has detailed emergency response plans that are documented in the Standard Operation Procedures available to all BSL3 personnel. The emergency response procedures are discussed with BSL3 users at the initial training for BSL3 entry and annually thereafter. Furthermore, specific scenarios for incidents are discussed during monthly BSL3 users meetings and at the BSL3 users annual refresher training day. Emergency simulations and drills are also performed.