Used cell and tissue culture media can be worse than unsightly; discarded media can contain biological hazards! Here are some guidelines to dispose of used media and help keep your lab running safely:

• Laboratory vacuum systems should consist of a collection flask, overflow flask, and in-line HEPA filter. See Figure 2 in the Biological Safety Manual.
• An appropriate disinfectant should be added to the collection flask before you start collecting media. In most cases, adding enough bleach to bring the final volume to 10% will properly disinfect cell- or tissue-culture media.
  • Reminder: Any media used to culture human cells, biological agents, or pathogens, that contains recombinant organisms, or contains BBP-materials, must be disinfected before disposal.
  • Check the expiration date on your bleach before its use.
  • In most cases, allowing 20-30 minutes for the bleach to disinfect the media is satisfactory.
  • If you are unsure what disinfectant would be best, please contact us.
• Properly disinfected liquid media can be disposed of in the sewer as long as it does not also contain chemical or radiological hazards.
• Vacuum flasks should be emptied regularly. EHS recommends emptying your flasks at least once per week. Don’t overfill your flasks. Maximum collection volume should not exceed two-thirds of the flask’s capacity.
• If your laboratory’s flasks have sat for longer or have visible growth, an additional disinfectant should be added and allowed 20-30 minutes contact time before disposal.
• Any flasks that are on the floor must be in a leak-proof secondary container.