Editing Biosafety level (section)

=== Biosafety level 3 ===
[[File:Influenza virus research.jpg|thumb|Dr Terrence Tumpey at US [[Centers for Disease Control]], [[Atlanta]], Georgia, US, working with [[influenza virus]] under biosafety level 3 conditions, with [[Powered air-purifying respirator|respirator]] inside a [[biosafety cabinet]] (BSC).]]

Biosafety level 3 is appropriate for work involving microbes which can cause serious and potentially lethal disease via the inhalation route.<ref name=CDCBiosafety/> This type of work can be done in clinical, diagnostic, teaching, research, or production facilities.<ref name=richmond/> Here, the precautions undertaken in BSL-1 and BSL-2 labs are followed, as well as additional measures including:
* A laboratory-specific biosafety manual must be drafted which details how the laboratory will operate in compliance with all safety requirements.<ref name=CDCBiosafety/>
* All laboratory personnel are provided medical surveillance and offered relevant immunizations (where available) to reduce the risk of an accidental or unnoticed infection.<ref name=CDCBiosafety/>
* All procedures involving infectious material must be done within a [[biosafety cabinet]].<ref name=CDCBiosafety/>
* Lab personnel must wear solid-front protective clothing (i.e. gowns that tie in the back). This cannot be worn outside of the lab and must be discarded or decontaminated after each use.<ref name=CDCBiosafety/>

Also, the facility which houses the BSL-3 lab must have certain features to ensure appropriate containment. The entrance to the lab must be separated from areas of the building with unrestricted traffic flow.<ref name=CDCBiosafety/> Also, the lab must be behind two sets of self-closing doors (to reduce the risk of aerosols escaping).<ref name=richmond/> The construction of the lab is such that it can be easily cleaned. Carpets are not permitted, and any seams in the floors, walls, and ceilings are sealed to allow easy cleaning and decontamination.<ref name=CDCBiosafety/> Also, windows must be sealed, and a ventilation system installed which forces air to flow from the "clean" areas of the lab to the areas where infectious agents are handled.<ref name=CDCBiosafety/> Air from the lab must be filtered before it can be recirculated.<ref name=CDCBiosafety/>

A 2015 study by ''[[USA Today]]'' journalists, identified more than 200 lab sites in the U.S. that were accredited biosafety levels 3 or 4.<ref name="pcnp">{{cite news |last1=Penzenstadler |first1=Nick |title=State incidents highlight bioterror lab concerns |url=https://www.postcrescent.com/story/news/investigations/2015/05/28/state-incidents-highlight-bioterror-lab-concerns/28089943/ |agency=USA Today Network |publisher=Post Crescent |date=28 May 2015}}</ref> The Proceedings of a Workshop on "Developing Norms for the Provision of Biological Laboratories in Low-Resource Contexts" provides a list of BSL-3 laboratories in those countries.<ref name="bsl3low">{{cite news |title=APPENDIX E LIST OF LABS IDENTIFIED IN LOW-RESOURCE COUNTRIES |url=https://www.nap.edu/read/25311/chapter/13 |access-date=4 February 2021 |publisher=National Academy of Sciences |date=2019}}</ref>

Biosafety level 3 is commonly used for research and diagnostic work involving various microbes which can be transmitted by aerosol and/or cause severe disease. These include ''[[Francisella tularensis]]'', ''[[Mycobacterium tuberculosis]]'', ''[[Chlamydia psittaci]]'', [[Venezuelan equine encephalitis virus]], [[Eastern equine encephalitis virus]], [[SARS coronavirus|SARS-CoV-1]], [[Middle East respiratory syndrome-related coronavirus|MERS-CoV]], ''[[Coxiella burnetii]]'', [[Rift Valley fever virus]], ''[[Rickettsia rickettsii]]'', several species of ''[[Brucella]]'', [[chikungunya]], [[yellow fever virus]], [[West Nile virus]], and ''[[Yersinia pestis]]''.<ref name=BMBLRecs/>