CDC Biosafety in Microbiological and Biomedical Laboratories (BMBL)

Overview

The CDC/NIH publication "Biosafety in Microbiological and Biomedical Laboratories" (BMBL), currently in its 6th edition, serves as the cornerstone guidance for biosafety practices in laboratories handling infectious microorganisms and hazardous biological materials. While not a federal regulation with force of law, BMBL is universally recognized as the standard of practice and is referenced in numerous federal and state regulations, institutional policies, and accreditation requirements.

Scope and Applicability

Who Should Follow BMBL

Primary Users:

• Research laboratories (academic, government, commercial)


• Clinical and diagnostic laboratories


• Production facilities for biologicals


• Biotechnology companies


• Pharmaceutical development facilities


• Teaching laboratories


• Veterinary diagnostic and research facilities

Massachusetts Context:
Massachusetts, home to the world's highest concentration of biotechnology companies and leading research institutions (Harvard Medical School, MIT, Boston University, numerous biotech firms in Cambridge/Boston), has hundreds of facilities that must implement BMBL guidelines. The state's Department of Public Health oversees laboratory safety and references BMBL standards in regulatory oversight.

Biosafety Levels (BSL)

BMBL defines four biosafety levels (BSL-1 through BSL-4) based on risk assessment:

BSL-1: Basic Level - Minimal Risk

Characteristics:

• Well-characterized agents not known to consistently cause disease in healthy adults


• Examples: non-pathogenic E. coli, Bacillus subtilis


• Suitable for teaching laboratories and basic research

Requirements:

• Standard microbiological practices


• Open bench work permissible


• No special containment equipment required


• Hand washing sinks required


• Basic PPE (lab coats, gloves, eye protection as needed)

BSL-2: Moderate Risk

Characteristics:

• Agents associated with human disease


• Routes of transmission: percutaneous injury, ingestion, mucous membrane exposure


• Examples: Staphylococcus aureus, Hepatitis B, common diagnostic specimens


• Most clinical and diagnostic laboratories operate at BSL-2

Requirements:

• BSL-1 practices PLUS:


• Limited access when work is in progress


• Biological safety cabinets (BSCs) for procedures that may generate aerosols


• Autoclave or other decontamination method on-site


• Biohazard warning signs


• Sharps precautions


• Biosafety manual defining waste decontamination


• Annual training in laboratory procedures

BSL-3: High Risk - Serious or Potentially Lethal Disease

Characteristics:

• Indigenous or exotic agents with potential for aerosol transmission


• Disease may have serious or lethal consequences


• Examples: Mycobacterium tuberculosis, SARS-CoV-2 (for certain procedures), West Nile virus, certain fungal pathogens


• Specialized research and some clinical laboratories

Requirements:

• BSL-2 practices PLUS:


• Controlled access - only authorized personnel


• Decontamination of all waste


• Decontamination of laboratory clothing before laundering


• Baseline serum banking for personnel


• Directional airflow (inward)


• Sustained directional airflow


• HEPA filtration of exhausted air


• Biological safety cabinets for all manipulations


• Double-door autoclave for waste decontamination


• Hands-free or automatically operated sinks


• Sealed penetrations in floors, walls, ceilings


• Self-closing, locking doors

Personnel Requirements:

• Specialized training


• Medical surveillance program


• Demonstration of proficiency

BSL-4: Maximum Containment - Dangerous and Exotic Agents

Characteristics:

• Dangerous/exotic agents with high risk of life-threatening disease


• Aerosol transmission or unknown transmission


• No available vaccine or treatment


• Examples: Ebola virus, Marburg virus, Lassa fever virus


• Very few facilities in the United States (none in Massachusetts)

Requirements:

• BSL-3 practices PLUS:


• Complete isolation from other areas


• Dedicated building or isolated zone


• Class III biological safety cabinet or positive pressure suits


• Change clothing before entering


• Shower on exit


• Decontaminate all materials on exit


• Dedicated supply and exhaust air systems


• HEPA filtration


• Negative pressure


• Backup power systems


• Extensive training and medical surveillance

Core Biosafety Principles

1. Risk Assessment

Before beginning work:

• Identify hazards (infectious agents, toxins, allergens)


• Assess likelihood of exposure


• Consider routes of transmission


• Evaluate consequences of infection


• Determine appropriate biosafety level


• Select appropriate containment and practices

Massachusetts-Specific Considerations:

• State regulations for select agents and toxins


• Local institutional biosafety committees (IBCs)


• Environmental health and safety office requirements

2. Containment Strategy

Primary Containment:

• Physical barriers between personnel and infectious materials


• Biological safety cabinets (BSCs)


• Closed containers


• Personal protective equipment


• Safe work practices

Secondary Containment:

• Facility design and operational practices


• Separation from public areas


• Controlled access


• Directional airflow


• Specialized air handling systems


• Decontamination facilities

3. Standard Microbiological Practices

Access Control:

• Limit access to trained personnel only


• Post biohazard warning signs


• Keep doors closed when work in progress


• Children under 16 not permitted in lab

Personal Protection:

• Lab coats, gowns, or uniforms


• Eye protection when needed


• Gloves when handling infectious materials


• Remove PPE before leaving laboratory


• No PPE in non-laboratory areas

Hand Hygiene:

• Wash hands after handling infectious materials


• Wash hands after removing gloves


• Wash hands before leaving laboratory


• Use antiseptic soap when appropriate

Decontamination and Waste:

• Decontaminate work surfaces after completion of work


• Daily decontamination of work surfaces


• Decontaminate all infectious materials before disposal


• Use validated decontamination methods (autoclave, chemical)


• Properly label and segregate biohazardous waste

Sharps Safety:

• Use safety-engineered sharps


• Never recap needles


• Dispose of sharps in puncture-resistant containers


• Minimize use of sharps when alternatives exist

Procedures:

• Minimize creation of splashes and aerosols


• Use biosafety cabinets for aerosol-generating procedures


• No eating, drinking, smoking, or applying cosmetics in lab


• No mouth pipetting


• Minimize use of sharps

4. Equipment and Engineering Controls

Biological Safety Cabinets (BSCs):

• Primary containment device for infectious materials


• Three classes (Class I, II, III) with different applications


• Annual certification required


• Proper placement and use critical


• Work at least 4 inches inside the cabinet


• Allow air barrier to stabilize before beginning work


• Clean and decontaminate before service

Class I BSC:

• Personnel and environmental protection


• No product protection


• Similar to chemical fume hood but with HEPA filtration

Class II BSC:

• Personnel, environmental, AND product protection


• Most common in biomedical laboratories


• Four types (A1, A2, B1, B2) with different airflow patterns


• Must be certified annually and after relocation

Class III BSC:

• Maximum containment


• Gas-tight enclosure


• Operations conducted through attached rubber gloves


• Supply air HEPA filtered


• Exhaust air double-HEPA filtered


• Required for BSL-4 work

Autoclaves:

• Must be validated and tested regularly


• Biological indicators used to verify efficacy


• Chemical indicators show items exposed to process


• Proper loading critical for effectiveness


• Documentation required (time, temperature, pressure)

5. Laboratory Design

Space Planning:

• Adequate space for safe conduct of work


• Easily cleanable surfaces


• Impervious to water and chemical resistant


• Furnishings minimal and easily cleanable


• Bench tops impervious and resistant to acids, alkalis, solvents

Utilities:

• Hands-free or automatically operated sinks


• Eyewash stations accessible


• Safety showers when appropriate


• Vacuum lines protected with HEPA filters


• Gas lines with appropriate safety features

HVAC Systems:

• Adequate air changes per hour


• Proper directional airflow (BSL-3, BSL-4)


• HEPA filtration of exhaust (BSL-3, BSL-4)


• Negative pressure relative to corridors (BSL-3, BSL-4)


• Airlocks or double-door entry (BSL-3, BSL-4)

Biosafety Program Administration

Institutional Biosafety Committee (IBC)

Required for:

• Institutions receiving NIH funding for recombinant DNA research


• Highly recommended for all institutions with biohazardous materials

Responsibilities:

• Review and approve research protocols


• Conduct periodic inspections


• Adopt and implement biosafety standards


• Report significant problems to NIH (when applicable)


• Review and approve emergency response procedures

Composition:

• Minimum 5 members


• At least 2 community members


• Expertise in recombinant DNA, biosafety, and relevant research areas

Biosafety Officer (BSO)

Responsibilities:

• Day-to-day oversight of biosafety program


• Technical expertise and consultation


• IBC support and coordination


• Training program development and delivery


• Incident investigation and response


• Regulatory compliance oversight


• Interface with regulatory agencies

Occupational Health Program

Components:

• Pre-placement medical evaluation


• Hazard-specific training


• Medical surveillance


• Exposure assessment and monitoring


• Post-exposure management


• Immunization programs when appropriate


• Health records maintenance


• Confidentiality protections

Vaccinations:

• Hepatitis B for personnel at risk


• Other vaccines based on risk assessment (e.g., rabies for certain work)


• Documentation of vaccination status


• Medical contraindications documented

Training Requirements

Initial Training:

• Biosafety principles and practices


• Hazards specific to work being performed


• Facility-specific procedures


• Emergency procedures


• Use of engineering controls (BSCs, autoclaves)


• PPE selection and use


• Waste management procedures

Ongoing Training:

• Annual refresher training


• Training after procedure changes


• Training after incidents


• Documentation required


• Competency demonstration

Agent-Specific Practices

Bloodborne Pathogens

• Universal precautions (treat all blood as potentially infectious)


• Sharps safety paramount


• Hepatitis B vaccination


• Exposure control plan required by OSHA

Mycobacterium tuberculosis

• BSL-3 practices for M. tuberculosis


• Respiratory protection (fit-tested N95 respirators minimum)


• Negative pressure rooms


• Medical surveillance including baseline and periodic TB testing


• Post-exposure prophylaxis protocols

Select Agents and Toxins

• Regulated by CDC/APHIS under Federal Select Agent Program


• Registration required for possession


• Enhanced security measures


• Personnel reliability program (background checks)


• Inventory tracking and accountability


• Incident reporting requirements


• Security plan and emergency response plan

Recombinant DNA

• NIH Guidelines for Research Involving Recombinant or Synthetic Nucleic Acid Molecules


• IBC review and approval


• Risk assessment based on insert and vector


• Containment level determined by risk assessment


• Reporting to NIH when required

Decontamination and Waste Management

Decontamination Methods

Autoclaving (Steam Sterilization):

• Most reliable method


• Typical: 121°C (250°F) for 20-60 minutes or 134°C (270°F) for 10-30 minutes


• Biological indicators to verify


• Must penetrate all materials


• Proper loading critical

Chemical Disinfection:

• EPA-registered disinfectants


• Appropriate for surface decontamination


• Contact time critical


• Concentration matters (follow manufacturer's instructions)


• Common agents: bleach (sodium hypochlorite), phenolics, quaternary ammonium compounds

Incineration:

• Complete destruction


• Used for animal carcasses, sharps, pathological waste


• Regulated by EPA and state agencies

Waste Segregation and Disposal

Regulated Medical Waste (RMW):

• Autoclaved or incinerated before disposal


• Red bags or containers with biohazard symbol


• Tracked from generation to final disposal


• Manifests required in some states

Sharps:

• Puncture-resistant containers


• Autoclaved or incinerated


• Never overfill containers


• Close containers when 3/4 full

Chemical Waste:

• Segregated from biological waste


• Hazardous waste regulations apply (RCRA)


• No autoclaving with chemicals (dangerous reactions possible)

Mixed Waste:

• Contains both hazardous chemicals and infectious agents


• Most difficult to manage


• Requires careful planning to minimize generation

Emergency Response

Spill Response

Small Spills (<10 mL):

• Alert others in area


• Don appropriate PPE


• Cover spill with absorbent material


• Apply disinfectant in circular motion from outside to center


• Allow contact time (typically 20-30 minutes)


• Clean up and dispose as RMW


• Decontaminate area

Large Spills (>10 mL):

• Evacuate area if necessary


• Alert others


• Contain spill if safely possible


• Contact biosafety officer or emergency response team


• Post sign to prevent entry


• Allow aerosols to settle (30 minutes to 1 hour)


• Trained personnel clean up with appropriate PPE

BSC Spills:

• Continue cabinet operation


• Alert others


• Contain and clean immediately if possible


• If extensive, decontaminate entire cabinet


• May require surface and/or gaseous decontamination

Exposure Incidents

Immediate Actions:

• Remove contaminated clothing


• Wash exposed area thoroughly (15 minutes for eyes, 10 minutes for skin)


• Seek medical evaluation immediately


• Report to supervisor and occupational health

Follow-up:

• Medical evaluation and treatment


• Post-exposure prophylaxis when appropriate


• Incident investigation


• Corrective actions


• Documentation

Laboratory Acquired Infections (LAIs)

Recognition:

• Awareness of symptoms


• Medical surveillance


• Prompt reporting


• Medical evaluation

Investigation:

• Determine source and route of exposure


• Identify contributing factors


• Implement corrective actions


• Prevent recurrence

Reporting:

• Institutional reporting (IBC, administration)


• Regulatory reporting when required (select agents, OSHA)


• Lessons learned shared appropriately

Regulatory Compliance

Federal Regulations

OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030):

• Applies to occupational exposure to blood


• Exposure control plan required


• Hepatitis B vaccination


• Engineering controls and PPE


• Training and recordkeeping

CDC/APHIS Select Agent Regulations (42 CFR Part 73):

• Registration for possession of select agents


• Security and training requirements


• Incident reporting


• Inspections and compliance

NIH Guidelines:

• Recombinant DNA research


• IBC requirements


• Containment practices

State Regulations

Massachusetts-Specific:

• Department of Public Health laboratory regulations


• Waste management regulations (310 CMR 15.000)


• Environmental health and safety oversight


• Institutional requirements vary

Massachusetts Biotechnology Industry Context

Massachusetts biotech companies and research institutions must implement BMBL principles while balancing:

Research Innovation:

• Cutting-edge research with novel organisms


• Risk assessments for new agents and procedures


• Adaptive biosafety practices

Regulatory Compliance:

• FDA requirements for biologics production


• EPA oversight of certain activities


• State and local regulations


• Institutional policies

Operational Efficiency:

• Cost-effective biosafety solutions


• Scalable programs for growing companies


• Integration with quality systems

Talent Management:

• Training programs for diverse workforce


• Biosafety culture development


• Retention through safety commitment

Best Practices for Massachusetts Laboratories

1. Conduct comprehensive risk assessments before beginning new work


2. Implement layered biosafety controls (engineering, administrative, PPE)


3. Provide thorough training and competency verification


4. Maintain and certify equipment regularly


5. Document everything (training, incidents, corrective actions)


6. Foster a culture of biosafety - leadership commitment essential


7. Engage with biosafety professionals (American Biological Safety Association, local networks)


8. Stay current with BMBL updates and new guidance


9. Plan for emergencies and practice response


10. Integrate biosafety with other programs (occupational health, environmental health and safety, quality)

Resources

Official BMBL:

• Free download from CDC website


• 6th Edition (2020) is current version


• Updates published periodically

Professional Organizations:

• American Biological Safety Association (ABSA International)


• Local biosafety associations and networks

Regulatory Agencies:

• CDC Division of Select Agents and Toxins


• NIH Office of Science Policy


• OSHA


• EPA


• Massachusetts Department of Public Health

Key Takeaways

1. BMBL is the standard for biosafety in laboratories


2. Risk assessment drives biosafety decisions - one size does not fit all


3. Four biosafety levels address different risk profiles


4. Multiple barriers provide defense in depth


5. Training and culture are as important as equipment


6. Emergency preparedness essential for all laboratories


7. Regulatory compliance requires understanding multiple frameworks


8. Massachusetts context demands excellence in biosafety