Biosafety Levels for Animal Use

Summary of Recommended Biosafety Levels for Activities in Which Experimentally or Naturally Infected Vertebrate Animals Are Used
BSL Agents Practices Safety Equipment (Primary Barriers) Facilities (Secondary Barriers)
1 Not known to consistently cause disease in healthy adults Standard animal care and management practices, including appropriate medical surveillance programs As required for normal care of each species. Standard animal facility
  • No recirculation of exhaust air
  • Directional air flow recommended
  • Handwashing sink recommended
2 Associated with human disease. Hazard = percutaneous injury, ingestion, mucous membrane exposure ABSL-1 practice plus:
  • Limited access
  • Biohazard warning signs
  • Sharps precautions
  • Biosafety manual
  • Decontamination of all infectious wastes and of animal cages prior to washing
ABSL-1 equipment plus primary barriers: containment equipment appropriate for animal species; PPEs: laboratory coats, gloves, face and respiratory protection as needed ABSL-1 facility plus:
  • Autoclave available
  • Handwashing sink available
  • Mechanical cage washer used
3 Indigenous or exotic agents with potential for aerosol transmission; disease may have serious health effects ABSL-2 practice plus:
  • Controlled access
  • Decontamination of clothing before laundering
  • Cages decontaminated before bedding removed
  • Disinfectant foot bath as needed
ABSL-2 equipment plus:
  • Containment equipment for housing animals and cage dumping activities
  • BSCs available for manipulative procedures (inoculation, necropsy) that may create infectious aerosols.  PPEs: appropriate respiratory protection
ABSL-2 facility plus:
  • Physical separation from access corridors
  • Self-closing, double-door access
  • Sealed penetrations
  • Sealed windows
  • Autoclave available in facility
4 Dangerous/exotic agents which pose high risk of life-threatening disease, aerosol-transmitted lab infections; or related agents with unknown risk of transmission ABSL-3 practice plus:
  • Entrance through change room where personal clothing is removed and laboratory clothing is put on; shower on exiting
  • All wastes are decontaminated before removal from the facility
ABSL-3 equipment plus:
  • Maximum containment equipment (i.e., Class III BSC or partial containment equipment in combination with full body, air-supplied positive-pressure personnel suit) used for all procedures and activities
ABSL-3 facility plus:
  • Separate building or isolated zone
  • Dedicated supply and exhaust, vacuum and decontamination systems
  • Other requirements outlines in the text

CDC/NIH Biosafety in Microbiological and Biomedical Laboratories; 5th Edition