The Laboratory Biosafety

Laboratory Biosafety Levels

Essential guidelines for Biosafety Level 1 and 2 Laboratories:

The following guidelines have been formulated by CDC-NIH in Biosafety in Microbiological and Biomedical Laboratories 4th Edition. Each laboratory should adopt standard operational procedures from these guidelines according to the type of work being carried out in their lab by identifying potential hazards and specifying practices and procedures to eliminate or minimize such hazards. Such operational procedures should be logged and made available in the form of a laboratory manual.

Laboratory Biosafety Level Criteria

There are four Biosafety levels for activities involving infectious microorganisms and laboratory animals. The levels are designated in ascending order, by degree of protection provided to personnel, the environment, and the community.

Biosafety Level 1 (BSL-1)

Biosafety Level 1 is suitable for work involving well-characterized agents not known to consistently cause disease in healthy adult humans, and may cause minimal potential hazard to laboratory personnel and the environment e.g. Bacillus subtilis, Naegleria gruberi, infectious canine hepatitis virus. 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. Special containment equipment or facility design is neither required nor generally used. 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.

The following standard and special practices, safety equipment and facilities apply to agents assigned to Biosafety Level 1:

A. Standard Microbiological Practices
  • Access to the laboratory is limited or restricted when experiments or work with cultures and specimens are in progress.
  • Persons wash their hands after they handle viable materials, after removing gloves, and before leaving the laboratory.
  • Eating, drinking, smoking, handling contact lenses, applying cosmetics, and storing food for human use are not permitted in the work areas. Persons who wear contact lenses in laboratories should also wear goggles or a face shield. Food is stored outside the work area in cabinets or refrigerators designated and used for this purpose only.
  • Mouth pipetting is prohibited; mechanical pipetting devices are used.
  • Policies for the safe handling of sharps are instituted.
  • All procedures are performed carefully to minimize the creation of splashes or aerosols.
  • Work surfaces are decontaminated at least once a day and after any spill of viable material.
  • All cultures, stocks, and other regulated wastes are decontaminated before disposal by an approved decontamination method such as autoclaving. Materials to be decontaminated outside of the immediate laboratory are to be placed in a durable, leak-proof container and closed for transport from the laboratory. Materials to be decontaminated outside of the immediate laboratory are packaged in accordance with applicable local, state, and federal regulations before removal from the facility.
  • A biohazard sign can be posted at the entrance to the laboratory whenever infectious agents are present. The sign may include the name of the agent(s) in use and the name and phone number of the investigator.
  • An insect and rodent control program is in effect.
B. Special Practices: None
C. Safety Equipment (Primary Barriers)
  • Special containment devices or equipment such as biological safety cabinets are generally not required for manipulations of agents assigned to Biosafety Level 1.
  • It is recommended that laboratory coats or gowns be worn to prevent contamination of street clothes.
  • Gloves should be worn if the skin on the hands is broken or if a rash is present.
  • Protective eyewear should be worn for conduct of procedures in which splashes of microorganisms or other hazardous materials are anticipated.
D. Laboratory Facilities (Secondary Barriers)
  • Laboratories should have doors for access control.
  • Each laboratory contains a sink for hand washing.
  • The laboratory is designed so that it can be easily cleaned. Carpets and rugs in laboratories are not appropriate.
  • Bench tops are impervious to water and are resistant to moderate heat and the organic solvents, acids, alkalis, and chemicals used to decontaminate the work surface and equipment.
  • Laboratory furniture is capable of supporting anticipated loading and uses. Spaces between benches, cabinets, and equipment are accessible for cleaning.
  • Laboratory windows that open to the exterior should be fitted with fly screens.

Biosafety Level 2 (BSL-2)

Biosafety Level 2 is similar to Biosafety Level 1 and is suitable for work involving agents of moderate potential hazard to personnel and the environment that are present in the community and associated with human disease of varying severity. With good microbiological techniques, these agents can be used safely in activities conducted on the open bench, provided the potential for producing splashes or aerosols is low. Hepatitis B virus, HIV, the salmonellae, and Toxoplasma spp. are representative of microorganisms assigned to this containment level. It differs from BSL-1 in that (1) laboratory personnel have specific training in handling pathogenic agents and are directed by competent scientists; (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.

The following standard and special practices, safety equipment, and facilities apply to agents assigned to Biosafety Level 2:

A. Standard Microbiological Practices
  • Access to the laboratory is limited or restricted when experiments are in progress.
  • Persons wash their hands after they handle viable materials, after removing gloves, and before leaving the laboratory.
  • Eating, drinking, smoking, handling contact lenses, and applying cosmetics are not permitted in the work areas. Food is stored outside the work area in cabinets or refrigerators designated for this purpose only.
  • Mouth pipetting is prohibited; mechanical pipetting devices are used.
  • Policies for the safe handling of sharps are instituted.
  • All procedures are performed carefully to minimize the creation of splashes or aerosols.
  • Work surfaces are decontaminated at least once a day and after any spill of viable material.
  • All cultures, stocks, and other regulated wastes are decontaminated before disposal by an approved decontamination method.
  • A biohazard sign is posted at the entrance to the laboratory whenever infectious agents are present. The sign includes the name of the agent(s) in use and the name and phone number of the investigator.
  • An insect and rodent control program is in effect.
B. Special Practices
  • The laboratory has a certified biosafety cabinet or other appropriate physical containment device for use with procedures that may create splashes or aerosols of infectious materials.
  • The laboratory has a sink for hand washing and a vacuum system for safe removal of liquid waste.
C. Safety Equipment (Primary Barriers)
  • Biological safety cabinets are used for procedures that may generate infectious aerosols or splashes.
  • Laboratory coats or gowns, gloves, and protective eyewear are worn as needed.
D. Laboratory Facilities (Secondary Barriers)
  • Laboratories should have doors for access control and a sink for hand washing.
  • Laboratory surfaces are easily cleanable and impervious to water.
  • Laboratory furniture should be capable of supporting anticipated loading and uses, and spaces between benches and equipment should be accessible for cleaning.
  • Laboratory windows that open to the exterior should be fitted with fly screens.

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