Decontamination is any process that reduces biohazardous material (infectious agents, recombinant or synthetic nucleic acid molecules, human material, biological toxins, etc.) to an acceptable level, or one that is below the level necessary to cause infection. Acceptable levels will depend on the biohazardous material in question and the type of work being done. To select the proper decontamination procedure one must consider many factors including the biohazard's concentration and resistance to disinfectants, chemical compatibility with other materials present, surface being decontaminated, and hazards to humans, animals, and the environment associated with the disinfectant. Ineffective decontamination can provide a false sense of security and spread contamination. Acceptable decontamination procedures must be determined before work begins and must be included in the lab's Standard Operating Procedures (SOPs).
Note: All recombinant or synthetic nucleic acid molecule-containing waste, including Biosafety Level 1 material, must be decontaminated prior to disposal or disposed of as biohazard waste before being released from the laboratory. See attached Decontamination and Spill Clean-Up template. This template must be customized for each lab.
Chemical disinfection is highly effective when done correctly. Some biohazardous agents are more or less susceptible to certain disinfectants.
|Prions||BSE, vCJD, scrapie|
|Bacterial Spores||Bacillus, Geobacillus, Clostridium sp.|
|Helminth Eggs||Ascaris, Enterobius|
|Small non-enveloped viruses||Poliovirus, Parvoviruses, Papillomaviruses|
|Protozoan Cysts||Giardia, Acathomoeba|
|Fungal Spores||Aspergillus, Penicillium|
|Gram-negative Bacteria||E. coli, Salmonella spp.|
|Vegetative Fungi & Algae||Candida, Chlamydomonas|
|Vegetative Helminths & Protozoa||Ascaris, Cryptosporidium, Giardia|
|Large non-enveloped viruses||Adenoviruses, Rotaviruses|
|Gram-positive Bacteria||Staphylococcus, Streptococcus, Enterococcus|
|Enveloped viruses||HIV, Hepatitis B, Herpes Simplex Virus|
Choosing a Chemical Disinfectant
The effectiveness of chemical disinfectants will depend on the type of biohazardous material involved. Some chemical disinfectants can pose health hazardous and cause corrosion to surfaces. The goal is to choose a disinfectant that is highly effective for the biohazardous agent yet poses minimal risks to human health and of damage to surfaces and equipment.
|Type||Tips for Use||Advantages||Disadvantages|
|Quaternary Ammonium Compounds—QUATS (cationic detergents)||
|Bacteria||Very good||Good||Good||Good for gram positive|
|Enveloped Viruses||Very good||Good||Good||Good|
|Non-Enveloped Viruses||Very good||Fair**||Fair**||Not effective|
|Bacterial Spores||Good with high concentration||Not Effective||Not Effective||Not Effective|
|Protozoal Parasites*||Moderate with high concentration and long contact time (hours)||Not Effective||Not Effective||Fair (some quats at high concentration)|
|Biologically-Derived Toxins***||Concentration dependent||Not Effective||Not Effective||Not Effective|
|*hydrogen peroxide most effective
**check disinfectant susceptibility for individual virus
***For information, see the Biologically-Derived Toxins web page.
Gas or Vapor Decontamination
Is useful when contamination issues are persistent or when there is a need to decontaminate an entire space. More information on the types of chemicals used in this process can be found in Appendix B of the BMBL. If you are experiencing contamination issues, please contact BOHD for further guidance at (612) 626-6002.
Biosafety cabinets must be gas or vapor decontaminated prior to removal from use or being sent to ReUse. For more information, please see the BSC Certification and Maintenance web page.