Bio-safety & Universal Precautions


Biosafety is the measures employed to avoid infecting oneself, others or the environment when handling biohazard materials



Bio Hazard Symbol
Bio-Hazard Symbol

An agent of biological origin that has the capacity to produce deleterious effects on humans, i.e. microorganisms, toxins and allergens derived from those organisms.


  • Microorganisms such as viruses, bacteria, fungi, and parasites.
  • Blood and body fluids, as well as tissues from humans and animals.


Biosafety Levels

Four biosafety levels provide increasing degrees of protection against various pathogenic microorganisms

  • Level 1:
    • Suitable for work involving well-characterized agents not known to cause disease in healthy adult humans and of minimal potential hazard to laboratory personnel and the environment.
    • Examples: Bacillus subtilis, E. coli
  • Level 2:
    • Suitable for work involving agents of moderate potential hazard to personnel and the environment
    • Examples: Measles virus, Salmonellae, Toxoplasma species, Hepatitis B virus
  • Level 3:
    • Suitable for work with infectious agents which may cause serious or potentially lethal disease as a result of exposure by the inhalation route.
    • Example: Mycobacterium tuberculosis
  • Level 4:
    • Suitable for work with dangerous and exotic agents that pose a high individual risk of aerosol transmitted laboratory infections and life threatening disease.
    • Example: Ebola Zaire virus



Containment includes safe methods for managing infectious materials in the laboratory environment where they are being handled or maintained. 

Purpose: is to reduce or eliminate exposure of laboratory workers, other persons, and the outside environment to potentially hazardous agents.

Primary Containment: Protects personnel and the immediate laboratory environment from exposure to infectious agents

Provided by: good microbiological technique, appropriate safety equipment (including personal protective equipment), and vaccines (where applicable)

Secondary Containment: Protection of the environment external to the laboratory from exposure to infectious materials

Provided by: combination of facility design and operational practices


Safety Equipment: (Primary Barriers)

These are designed to remove or minimize exposures to hazardous biological materials.



Biological Safety Cabinets, safety centrifuge cup, personal protective equipment (PPE), such as gloves, coats, gowns, shoe covers, boots, respirators, face shields, safety glasses, or goggles


Biosafety Cabinets:

  • 3 Classes
  • Exhaust – HEPA (High Efficiency Particulate Air)

    BioSafety Cabinet Diagram
    Bio-Safety Cabinet Diagram


Class I:

⇒ Do not protect the work from contamination

⇒ Air entering cabinet is not filtered

Class II:

⇒ Each type recirculates different amount of air

⇒ Some are hard ducted, and some exhaust into the room

Class III:

⇒ Totally enclosed, ventilated cabinets

⇒ Work through portals with attached glove


Standard Precautions

  • Previously this was known as Universal Precautions. Standard Precautions are specific precautions designed to prevent harmful bacteria and viruses from infecting people who are providing first aid or health care.
  • As defined by the Centers for Disease Control (CDC); Standard Precautions are a set of practices designed to prevent the transmission of HIV, Hepatitis B and other blood borne pathogens (bacteria and viruses).
  • Under Standard Precautions, blood and other body fluids of all patients are considered potentially infectious.


Personal Protective Equipment:

  • Gloves / Aprons / Gowns Protective eyewear / Face shields / Masks


Standard Precautions also include:

  • Hand washing
  • Proper handling and disposal of needles and hospital waste.
  • Taking precautions to prevent injury from sharp instruments

Hand Washing:

Hand washing is the MOST IMPORTANT STEP in preventing the spread of disease!


  • Wet your hands with warm water.
  • Apply soap.
  • Rub hands together and scrub really well.
  • Be sure to get under fingernails and in between fingers.
  • Scrub for about 10-15 seconds.
  • Rinse hands of soap.
  • Dry hands well with a clean paper towel or cloth.


Gloves: When to wear gloves?

  • Anytime you may come in contact with blood or other body fluids such as urine, saliva, vomit, or the mucous membranes of the mouth or nose.
  • When touching skin that may have sores, open wounds, cuts, or scratches.
  • When handling any object that may have been soiled with blood or body fluids.
  • When you have a cut or scratch on your hands.



  • Standard Precautions recommend that you treat all bodily fluids as if they are infected with a blood-borne disease.
  • Personal protective equipment includes gloves, face shields or eyewear, gowns, aprons and masks.
  • Wash hands before putting on gloves and immediately after removing gloves.