Biohazardous Waste and Decontamination


The primary objective is to reduce the level of microbial contamination so that infection transmission is eliminated. Disinfection procedures must be effective and appropriate. The selection of a disinfectant is based on assessment of both the biohazardous agent(s) and the object to be decontaminated.

All laboratory workers must wash their hands with an appropriate disinfectant after handling infectious materials and removing gloves and before leaving the laboratory area.

Incidents that may result in exposure to infectious materials must be immediately evaluated and treated by staff properly trained and equipped to work with infectious material. In the event of physical contamination due to a splash or spill, the area must be immediately decontaminated with an appropriate disinfectant.  If the contamination is to a mucous membrane such as eyes, nose, mouth, etc., the area must be rinsed with running water for at least 15 minutes. All such incidents must be reported to the laboratory supervisor.

Equipment and Labware:
Laboratory equipment and working areas should be decontaminated after each use with infectious materials, as well as, after spills, splashes, or other potential contamination.

  1. Spills involving infectious materials must be contained, decontaminated, and cleaned up with an appropriate disinfectant by staff properly trained and equipped to work with infectious material.
  2. Equipment must be decontaminated before repair, maintenance, or removal from the laboratory.
  3. All consumable solid supplies must be autoclaved prior to disposal.
  4. All reusable supplies (i.e.- glassware) must be decontaminated with an appropriate disinfectant prior to re-use.
  5. Significant volumes of contaminated liquids must be autoclaved or treated with an appropriate disinfectant.

Cultures and stocks of infectious agents and associated biologicals including:

  • laboratory waste, biological production wastes, discarded live and attenuated vaccines, culture dishes, and related device
  • liquid human and animal waste, including blood and blood products and body fluids, but not including urine or materials stained with blood or body fluids.
  • pathological waste.
  • contaminated wastes from animals that have been exposed to agents infectious to humans, these being primarily research animals.
shall be placed in biohazard bags and decontaminated by autoclaving.

Aspirating Contaminated Liquids Safely:

One method to protect a house vacuum system during aspiration of infectious fluids. The left suction flask (A) is used to collect the contaminated fluids into a suitable decontamination solution; the right flask serves as a fluid overflow collection vessel. An in-line HEPA filter (C) is used to protect the vacuum system (D) from aerosolized microorganisms.( Biosafety in Microbiological and Biomedical Laboratories 5th edition (BMBL) Appendix A.)

Laboratory Areas:
Laboratory workers are required to decontaminate all working areas with an appropriate disinfectant after the use of biohazardous materials.

For additional detail refer to:Biosafety in Microbiological and Biomedical Laboratories 5th edition (BMBL) Appendix B.

See EPA List for Registered Disinfectants:


Autoclaved waste may be disposed in the regular trash once it is transferred to a black bag marked with the words, "Decontaminated Medical Waste". Please contact EH&S (extension 4196) for "Decontaminated Medical Waste" labels or for assistance with the disposal of biohazardous waste that cannot be autoclaved. Double or triple bagging may be required to avoid rupture or puncture of the bags.

Decontaminated liquids not containing any other hazardous substances, may be flushed down the drain.  

Sharps Disposal
Sharps require special handling, storage, and disposal procedures to protect laboratory users and waste handlers.  Sharps are objects that can be reasonably anticipated to puncture and penetrate the skin.  Sharps include, but are not limited to, the following: 

  • Needles
  • Scalpels
  • Razor and X-acto® blades
  • Syringes
  • Microscope slides and coverslips
  • Broken glass
  • Capillary tubes
  • Pasteur pipettes and pipette tips

All biohazardous sharps must be placed in a sharps container prior to disposal.  A sharps container must be of rigid plastic with close fitting top, leak-proof, puncture-resistant, break resistant and properly labeled with a universal biohazard symbol.

Disposal of Mixed waste

If you have biohazardous waste with another type of hazardous material such as radionuclide or hazardous chemicals, refer to the above "Mixed Waste" tab. 

Biohazardous Mixed Waste

Definition:  Biohazardous mixed-waste is biohazardous waste which falls into two or more different categories of hazardous materials.  Biohazardous waste that may also contain radioactive waste and/or (chemically) hazardous waste is defined as biohazardous mixed waste.  As a result, waste handling, disposal, and regulations are complex. Several different regulatory frameworks and federal agencies are involved. Whenever possible, it is best to avoid generating mixed wastes.

Biohazardous Waste that contains radioactive material
Biohazardous material contaminated with radionuclides must be treated as a radioactive waste with a biohazard label.  Radioactive biohazardous waste can be sterilized through the use of an autoclave or chemical inactivation but first must be approved by the RSO. Please consult with the Biosafety Officer for additional approved methods of sterilization.

Biohazardous Waste that contains hazardous chemicals
Biohazardous waste containing hazardous Chemical Waste must be treated as Hazardous Chemical Waste with a biohazard label.  When possible, disinfect the biohazardous part of the mix and then dispose of it as chemical waste. Hazardous chemical biohazardous waste should never be autoclaved without prior approval from the BSO.

Biohazardous Waste that contains both radioactive material and hazardous chemicals
If the biohazardous waste contains both radionuclides and hazardous chemicals, the material must be treated as a radioactive waste with a biohazard label and the hazardous chemical clearly identified on the container.  Radioactive biohazardous mixed waste should never be autoclaved without prior approval from the RSO.