Risk Assessment

An agent of biological origin that has the capacity to produce deleterious effects on humans.

These agents may include, but are not limited to:
  • bacteria
  • viruses
  • fungi
  • recombinant DNA
  • pathogens carried by cultured cell lines
  • toxins and allergens derived from biological organisms
  • bloodborne pathogens
Biosafety Levels

For each biosafety level,  a combination of laboratory practices and techniques, safety equipment, and laboratory facilities is required to protect the worker, the population and the environment from exposure to biohazardous materials (refer to BMBL for details). 

Biosafety level 1 (BSL-1): is the basic level of protection and is appropriate for agents that are not known to cause disease in normal, healthy humans.

Biosafety level 2 (BSL-2): is appropriate for handling moderate-risk agents that cause human disease of varying severity by ingestion or through percutaneous or mucous membrane exposure. All human and primate-derived materials must be treated at BSL-2 or above, because they are at a higher risk for bloodborne pathogens.

Biosafety level 3 (BSL-3): is appropriate for agents with a known potential for aerosol transmission, for agents that may cause serious and potentially lethal infections and that are indigenous or exotic in origin

Biosafety level 4 (BSL-4): is appropriate for exotic agents that pose a high individual risk of life-threatening disease by infectious aerosols and for which no treatment is available.

Biosafety Level is assigned based on the Risk Group of the materials to be utilized in the project and a risk assessment of the manipulations involved. See the above "Risk Group" tab for more details

Risk Groups

Biosafety Level for a given project is assigned based upon the highest Risk Group material utilized.

  • Risk Group 1 (RG1) agents are not associated with disease in healthy adult humans.
  • Risk Group 2 (RG2) agents are associated with human disease which is rarely serious and for which preventive or therapeutic interventions are often available.
  • Risk Group 3 (RG3) agents are associated with serious or lethal human disease for which preventive or therapeutic interventions may be available.
  • Risk Group 4 (RG4) agents are likely to cause serious or lethal human disease for which preventive or therapeutic interventions are not usually available.

Risk Group Determination

The applicant should consult the following resources to make a conservative determination of Risk Group (and Biosafety Level).

Resources for Risk Group Determination

  •  These materials are not formally classified as Risk Group agents by NIH; however, their capacity to host infectious agents requires employment of  BSL-2 or greater procedures and containment.


Routes of Exposure
and Minimization

 When conducting a risk assessment for your IBC Application, it is necessary to evaluate the potential routes of exposure, and provide details on how you will control these exposures. The below table can be referenced as a checklist for common routes of exposure found in a microbiological lab and can be used to develop associated controls for minimizing these exposures.

Route of Exposure

Organs Involved

Common Lab Exposures Sources



(Skin or Mucus Membrane)



Mucus Membranes - Eyes, Mouth and Nose
  • Spills and Splashes
  • Contaminated work surfaces or equipment
  • Use gloves, goggles, face shields and protective clothing
  • Decontaminate work surfaces regularly
  • Double contain potential sources of spills or splashes
  • Wash hands after biohazardous work and especially after removing gloves



Respiratory Tract (Nasal passages, trachea, larynx and lungs)

  • Spills and splashes
  • Aerosol producing equipment: blenders, sonicators tissue grinders
  • Aerosol from Dispensors: pipettors, syringes, pouring liquids
  • Centrifugation without sealed cup rotors
  • Many others….


  • Use a Biosafety cabinet whenever infectious aerosols may be generated
  • Use sealed cup rotors when centrifuging biohazardous material
  • Respirators may be used as a last resort



Digestive Tract (mouth, esophagus, stomach, intestine)

  • Eating, mouth pipetting, or accidental transfer of contaminated hands or objects to mouth
  • Use proper work practices, including the prohibition of mouth pipetting, eating, contact lenses manipulations or the use of cosmetics in the lab.


(Self inoculation by needles or cuts by sharp objects in the lab.)


Body Surfaces

  • Syringes and needles are the greatest source of inoculation injuries
  • Scalpels and broken glass and razor blades
  • Animal bites or scratches
  • Dispose entire syringe and needle directly into approved sharps safes without recapping or any other manipulations.
  • Devise methods that avoid the use of sharps or wear puncture resistant protective equipment.