Biological safety, also known as biosafety, helps protect laboratory employees from exposure to infectious agents, biological materials, human specimens, recombinant or synthetic nucleic acid materials, biological toxins, and other potentially hazardous biological materials. Effective laboratory biosafety combines hazard assessment, appropriate containment, safe work practices, personal protective equipment, decontamination, waste management, training, and emergency procedures.
Laboratories should evaluate the biological materials and procedures used in their operations and establish controls appropriate for the hazards involved. The precautions needed can vary considerably depending on the biological agent, concentration and volume of material, route of transmission, procedures performed, potential for aerosol generation, equipment used, and experience of laboratory personnel.
Biological Hazard Assessment
Before beginning work with potentially hazardous biological materials, the laboratory should evaluate the hazards associated with the material and the procedures that will be performed.
A biological risk assessment may consider:
- Biological agent or material being handled
- Pathogenicity and severity of disease
- Routes of transmission or exposure
- Infectious dose, when known
- Concentration and volume of material
- Potential for splashes, sprays, droplets, or aerosols
- Use of needles, scalpels, glass, or other sharps
- Centrifugation, vortexing, sonication, blending, or other aerosol-generating procedures
- Stability of the biological material in the environment
- Availability of vaccines, treatments, or post-exposure measures
- Experience and training of laboratory personnel
- Facility design and available containment equipment
- Decontamination and waste-disposal requirements
The results of the assessment should be used to determine appropriate laboratory practices, containment equipment, PPE, access restrictions, emergency procedures, and training.
Biosafety Levels
Laboratories working with biological agents may use Biosafety Levels (BSL-1 through BSL-4) to identify combinations of laboratory practices, safety equipment, containment measures, and facility features appropriate for the work being performed.
The appropriate biosafety level should not be selected solely by the name of an organism. The laboratory should consider the biological agent, procedures being performed, quantities and concentrations involved, potential routes of exposure, and other characteristics of the work.
In general:
BSL-1 applies to work involving well-characterized agents not known to consistently cause disease in healthy adults and presenting minimal potential hazard to laboratory personnel and the environment.
BSL-2 is used for work involving agents associated with human disease that pose moderate hazards to personnel and the environment. Access restrictions, additional training, appropriate PPE, and biological safety cabinets for procedures that may create infectious aerosols or splashes are commonly used.
BSL-3 involves additional containment practices and facility controls for agents that may cause serious or potentially lethal disease through inhalation exposure.
BSL-4 provides the highest level of containment and is reserved for particularly dangerous agents requiring highly specialized facilities, equipment, procedures, and training.
The appropriate containment level should be determined through a laboratory-specific biological risk assessment.
Biological Safety Cabinets
A Biological Safety Cabinet (BSC) is designed to provide containment when laboratory procedures may generate infectious aerosols, droplets, or splashes.
Depending on its class and configuration, a properly selected and operated BSC can help protect laboratory personnel, the surrounding environment, and—in many applications—the materials being handled.
Biological safety cabinets should:
- Be appropriate for the biological materials and procedures being performed.
- Be installed in a location that minimizes disruption of cabinet airflow.
- Be operated according to the manufacturer’s instructions and laboratory procedures.
- Be kept free of unnecessary equipment and materials that could interfere with airflow.
- Be decontaminated as appropriate following work and after spills.
- Be inspected, maintained, and certified at appropriate intervals.
- Be recertified when required after relocation or significant maintenance.
Employees should receive training before using a biological safety cabinet.
A biological safety cabinet is not the same as a chemical fume hood. Chemical fume hoods are primarily designed to control hazardous chemical vapors, gases, and fumes. Biological safety cabinets are designed primarily for containment of biological aerosols and particulates. The correct equipment must be selected for the hazard involved.
Preventing Aerosol Exposure
Many laboratory procedures can generate aerosols that may not be visible to employees.
Potential aerosol-generating activities include:
- Pipetting
- Vortexing and mixing
- Centrifugation
- Sonication
- Blending or homogenizing
- Opening pressurized or vacuum containers
- Pouring biological cultures
- Opening specimen containers
- Handling spills
- Manipulating needles and syringes
- Performing procedures involving high concentrations or volumes of biological material
Where potentially infectious aerosols may be generated, appropriate containment equipment and work practices should be used.
Sealed centrifuge rotors or safety cups may be appropriate when centrifuging hazardous biological materials. These devices should be opened using procedures that minimize potential exposure and, when warranted by the risk assessment, inside an appropriate biological safety cabinet.
Personal Protective Equipment
Laboratory PPE should be selected according to the biological materials and procedures involved.
Depending on the work, PPE may include:
- Laboratory coats or protective gowns
- Disposable or reusable gloves
- Safety glasses
- Chemical splash goggles
- Face shields
- Protective sleeves
- Closed-toe footwear
- Respiratory protection when required
Gloves should be changed when contaminated, damaged, or otherwise compromised and removed before touching clean surfaces or leaving designated laboratory areas.
Protective laboratory clothing should not be worn into offices, eating areas, or other locations where contamination could be transferred.
Respirators should not be substituted for appropriate engineering controls when those controls are feasible. When respirators are required, they must be used as part of an applicable respiratory protection program.
Bloodborne Pathogens
Laboratories that handle human blood, certain human body fluids, unfixed human tissues, or other potentially infectious materials (OPIM) may be subject to OSHA’s Bloodborne Pathogens Standard.
Where occupational exposure exists, required controls may include:
- Exposure determination
- Written Exposure Control Plan
- Universal Precautions
- Engineering and work-practice controls
- Appropriate PPE
- Safer sharps devices when applicable
- Hepatitis B vaccination
- Procedures for exposure incidents
- Post-exposure evaluation and follow-up
- Employee training
- Required labels and signs
- Medical and training records
- Sharps injury records when applicable
Bloodborne Pathogens requirements should be coordinated with the laboratory’s broader biological safety procedures.
Sharps Safety
Needles, scalpels, broken glass, pipettes, and other sharps can cause injuries and may introduce infectious materials directly into the body.
Laboratories should minimize unnecessary use of sharps whenever practical.
Employees should:
- Use safer sharps devices when required and appropriate.
- Avoid recapping, bending, breaking, or manipulating contaminated needles unless a specific procedure requires it and appropriate controls are used.
- Dispose of contaminated sharps promptly.
- Use approved puncture-resistant sharps containers.
- Keep sharps containers accessible and replace them before they become overfilled.
- Use mechanical methods such as forceps, tongs, or a brush and dustpan to handle broken contaminated glass rather than picking it up by hand.
Sharps injuries and potential biological exposures should be reported immediately according to laboratory procedures.
Hand Hygiene and Personal Practices
Good microbiological practices are fundamental to biological safety.
Employees should wash their hands after handling biological materials, after removing gloves, following potential contamination, and before leaving the laboratory.
Eating, drinking, smoking, applying cosmetics or lip balm, and handling contact lenses should not be permitted in areas where biological materials could create an exposure hazard.
Food and beverages should not be stored in refrigerators, freezers, cabinets, or other areas designated for biological materials.
Mouth pipetting is prohibited when handling blood or other potentially infectious materials and should not be used for laboratory work.
Decontamination
Work surfaces, equipment, and reusable materials should be decontaminated using methods appropriate for the biological materials involved.
Laboratories should establish procedures addressing:
- Routine surface decontamination
- Decontamination after spills
- Equipment decontamination
- Reusable laboratory equipment
- Biological safety cabinets
- Centrifuges and rotors
- Materials leaving containment areas
- Waste awaiting treatment or disposal
Disinfectants should be selected based on the organisms or biological materials involved, surface compatibility, required contact time, concentration, and manufacturer’s instructions.
Autoclaves and Biological Waste
Autoclaves may be used to treat certain biological materials and wastes through steam sterilization.
Where autoclaves are used, laboratories should establish procedures for:
- Appropriate waste preparation
- Container selection
- Safe loading and unloading
- Cycle selection
- Verification of treatment effectiveness
- Burn and steam-exposure prevention
- Equipment inspection and maintenance
- Employee training
Biological waste should be segregated, contained, labeled, stored, treated, and disposed of according to applicable federal, state, and local requirements.
Sharps should be placed in designated sharps containers rather than ordinary biological waste bags.
Biological Spill Response
Laboratories should establish procedures for biological spills based on the materials involved and the potential exposure.
Employees should know:
- When to evacuate or restrict access to the area
- Who should be notified
- What PPE is required
- What disinfectant or decontamination method should be used
- How long aerosols should be allowed to settle when applicable
- How contaminated materials should be collected
- How waste should be handled
- When medical evaluation may be necessary
- How exposures and incidents are reported
Employees should not attempt to clean a biological spill unless they have been trained and have the equipment necessary to respond safely.
Exposure Incidents
Potential exposure incidents may include:
- Needlesticks or cuts from contaminated sharps
- Splashes to the eyes, nose, or mouth
- Contact with damaged or non-intact skin
- Inhalation of potentially infectious aerosols
- Bites or scratches from laboratory animals
- Failure or loss of containment
- Significant biological spills
Employees should immediately follow the laboratory’s exposure-response procedures.
Depending on the material involved, response may include washing or flushing the affected area, notifying the supervisor or responsible safety personnel, medical evaluation, documenting the incident, identifying the biological material involved, and determining whether post-exposure treatment or follow-up is necessary.
Laboratory Access and Biosecurity
Access to laboratories handling biological hazards should be appropriate for the risks involved.
Controls may include:
- Authorized personnel only
- Laboratory hazard signage
- Biohazard warning signs
- Controlled doors or access systems
- Visitor procedures
- Escort requirements
- Restrictions during active procedures
- Secure storage of biological materials
- Inventory controls for designated materials
- Procedures for transporting materials within the facility
Higher-risk biological materials may require additional security, accountability, inventory, and regulatory controls.
Biological Material Transportation
Biological materials should be transported in a manner that prevents leakage, breakage, contamination, and employee exposure.
Transport within a facility may require:
- Closed primary containers
- Leak-resistant secondary containment
- Appropriate labeling
- Secure racks or carriers
- Separation from food and personal items
- Spill-response provisions
Shipment of infectious substances, diagnostic specimens, biological substances, dry ice, or other regulated materials outside the facility may be subject to additional packaging, labeling, documentation, and employee-training requirements.
Training
Employees who work with or around biological hazards should receive training appropriate to their assigned work and potential exposures.
Training may include:
- Biological hazards present in the laboratory
- Biosafety practices and procedures
- Risk assessment
- Biosafety levels
- Biological safety cabinet operation
- PPE selection and use
- Sharps safety
- Bloodborne Pathogens
- Hand hygiene
- Aerosol-generating procedures
- Decontamination
- Biological waste
- Spill response
- Exposure reporting
- Emergency procedures
- Laboratory access and security
Additional or refresher training should be provided when procedures, equipment, biological agents, or employee responsibilities change or when deficiencies indicate that additional training is necessary.
Biological Safety Is Part of the Laboratory Safety Program
Biological safety should be integrated into the laboratory’s overall safety-management system rather than treated as an isolated subject.
A comprehensive Laboratory Safety Manual may also address Chemical Hygiene, Hazard Communication, Chemical Storage and Compatibility, Laboratory PPE, Chemical Fume Hoods, Compressed Gases, Cryogenic Materials, Emergency Procedures, Hazardous Waste, Laboratory Equipment, Radiation, Lasers, Working Alone, Safety Training, Inspections, incident investigation, and other hazards applicable to the laboratory.
The biological safety procedures selected for a laboratory should reflect the biological agents, specimens, equipment, processes, facilities, and employee exposures actually present.
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