Your BSL-2 Lab Survival Guide
Welcome to BSL-2, where the experiments are awesome, but the clean-up is mandatory! What is a BSL-2? A BSL-2 is the second level of safety measures used in labs that work with common human pathogens. This includes bacteria like Staphylococcus, viruses such as influenza, human blood and body fluids, and parasites like Plasmodium (the malaria parasite) and Schistosoma (which causes schistosomiasis). If you’re working with cell lines, it automatically requires BSL-2 safety precautions.
1. The Disinfectant Dossier: Bleach and Alcohol
You've got two main heroes in your decontamination toolkit: Bleach (Sodium Hypochlorite) and Alcohol (usually 70% ethanol or isopropanol). You need to know when and how to use them.
Bleach: Your High-Power Disinfectant
Bleach is the champion for spills and heavy contamination, especially organic matter like blood or cell culture media. But you can't just dump it out of the bottle! Here’s why:
Why Bleach Should Never Be Mixed with Other Cleaning Agents
Seriously, never mix bleach with ammonia (often in glass cleaner) or acids. It creates toxic chlorine gas that can cause severe respiratory damage. If you're unsure what a cleaning agent contains, just stick to bleach and water.
2. Routine Bench Cleanup: Before and After
Treat your bench like a cutting board in a kitchen - it needs cleaning before and after every use!
Glove Up: put on your full PPE (lab coat, gloves, eye protection).
Pre-Clean: Remove any visible gunk (like dropped media or dirt) first. Organic matter can deactivate your disinfectant.
Soak and wait: liberally saturate the entire work surface with your 1:50 fresh bleach solution (or 70% alcohol).
Time is the Essence: Let it sit for the required contact time (e.g., ≥10 minutes for bleach). Walk away, check a protocol, but do not wipe it yet.
Final Steps: Wipe up with disposable towels, discard the towels into the biohazard waste, and finish with a water rinse if you used bleach.
3. Waste Management: Segregation is Survival
Your job doesn't end when the experiment is done. You must put waste in the correct stream. Mixing waste is dangerous and expensive!
4. Emergency Drill: Handling Biological Spills
A spill is stressful, but a plan makes it manageable. Follow these steps immediately, especially for high-risk spills like blood.
A spill is stressful, but a plan makes it manageable. Follow these steps immediately, especially for high-risk spills like blood.
Stop and alert: stop what you are doing. Immediately alert your colleagues and restrict the area. Get the spill kit.
Gear up: put on heavy-duty gloves, a clean lab coat, and eye protection.
Contain: gently cover the entire spill with absorbent material (paper towels, spill pads).
Attack: gently pour your strong 1:10 bleach solution over the spill, working from the outside edge inward to prevent splashing. Make sure the absorbent material is saturated.
Wait it Out: Step back and let the solution sit for a full 20−30 minutes.
Cleanup: use tongs or forceps (never your hands!) to pick up the saturated materials and place everything into a biohazard bag. Wipe the area a second time with fresh disinfectant.
Final steps: remove your gloves and other cleanup PPE, placing it in the biohazard bag as well. Wash your hands thoroughly.
Report: immediately report the spill to your PI and/or Biosafety Officer. If there was any chance of exposure (splash to eye/mouth/skin cut), follow the institution's exposure protocol first!
References
Centers for Disease Control and Prevention. (2008). Guideline for disinfection and sterilization in healthcare facilities. U.S. Department of Health and Human Services. https://www.cdc.gov/infection-control/media/pdfs/guideline-disinfection-h.pdf
Centers for Disease Control and Prevention. (2024). Chemical disinfectants: Sodium hypochlorite (bleach).
https://www.cdc.gov/infection-control/hcp/disinfection-sterilization/chemical-disinfectants.htmlNational Institutes of Health, Division of Occupational Health and Safety. (n.d.). Decontamination and disinfection. Office of Research Services. https://ors.od.nih.gov/sr/dohs/safety/laboratory/BioSafety/Pages/decontamination.aspx
Stanford Environmental Health & Safety. (n.d.). Sodium hypochlorite (bleach). Stanford University. https://ehs.stanford.edu/reference/sodium-hypochlorite-bleach
Massachusetts Institute of Technology, Environment, Health and Safety Office. (n.d.). Decontamination and disinfection. https://ehs.mit.edu/biological-program/decontamination-and-disinfection/
World Health Organization. (2020). How to prepare and use chlorine (bleach) solutions. https://www.who.int/docs/default-source/wpro---documents/wpro---pdf-infographics/covid-19/bleach-dilution-and-guidance-for-visitors-20200622.pdf
World Health Organization. (2014). Decontamination and spill management. In Laboratory biosafety manual (3rd ed.). https://www.ncbi.nlm.nih.gov/books/NBK138660/
University of Western Ontario. (2018). Guidelines for using sodium hypochlorite as a disinfectant for biological waste. https://www.uwo.ca/animal-research/doc/bleach-sop.pdf
University of Pittsburgh Medical Center, Hillman Research Pavilion. (2018). BSL-2+ safety manual (Flow Laboratory v6). https://hillmanresearch.upmc.edu/wp-content/uploads/2018/10/BSL2_Manual_Flow_Lab_v6.pdf
Pereira, S. S., & Pereira, A. M. (2021). Choosing the appropriate surface disinfectant. Journal of Applied Microbiology, 130(4), 1047–1060. https://pmc.ncbi.nlm.nih.gov/articles/PMC8224088/
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