Biologically Contaminated Waste

To prevent exposure of the public and contamination of the environment, all biological waste generated at MIT must be appropriately disinfected prior to final disposal (Massachusetts Department of Public Health State Sanitary Code Chapter VIII: 105 CMR 480.000). 


Biological waste includes any liquid, solid, or sharp material that has come in contact with viable biological material (including recombinant DNA or synthetic nucleic acids).  Examples are liquid bacterial or human cell cultures, gloves, petri dishes, pipette tips, needles and syringes, razor blades, etc. 


Researchers are responsible for all waste they generate from the moment they generate it until the moment it is inactivated. Please select the appropriate section below for guidance on how to handle your waste.




Biological Waste Flowchart


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Liquid Waste



  • Liquid waste include cultures, supernatants, media, or any liquids that contain or have come in contact with viable biological material
  • Use a chemical disinfectant at an appropriate concentration and contact time
    • Bleach
      • When using concentrated household bleach (5.25%  or greater sodium hypochlorite concentration), the final concentration should be  concentration of 10% (v/v) with an effective chlorine concentration of 5000 ppm
      • Contact time must be at least 20 minutes
      • We recommend Clorox germicidal bleach available in the VWR stockroom (eCat #89501-620)
    • Wescodyne
      • When using concentrated Wescodyne, the final concentration must be 1% with an effective iodine concentration of 125 ppm.
      • Contact time must be at least 20 minutes
    • Other disinfectants can be used.  Please see the Decontamination and disinfection webpage or consult with Biosafety Program for information.
  • Disposal:
    • Pour down sink drain and flush with water
    • Liquids should never be placed in the biowaste box
    • For disposal of small amounts of residual liquid, please see Solid Waste below
  • Perform disinfection in a fume hood or biosafety cabinet for liquids containing a pathogen or contaminated with an unknown microorganism

Special Considerations

  • Mixed biological and chemical hazardous waste:
    • Inactivate the biological component with a disinfectant that will not react with the chemicals - when in doubt, contact EHS for guidance
    • Send the inactivated solution out as chemical hazardous waste
  • Mixed biological and radioactive hazardous waste:
    • Inactivate the biological component with household bleach
    • Handle inactivated solution as radioactive liquid waste
  • Biological waste from commercial kits:
    • Examples include nucleic acid extraction kits from environmental samples (Qiagen, MoBio, etc.), plasmid and genomic DNA prep kits (Qiagen mini/midi/maxiprep kits), and others.
    • Kits that already inactivate the biological component (i.e. through lysis, chemical inactivation, or other means), do not need an additional chemical inactivation step
    • Kit waste must NEVER be bleached since certain chemicals in common lysis buffers react with bleach
    • Most kit waste must be sent out as hazardous chemical waste due hazardous chemicals in the lysis buffer (guanidine thiocyanate, guanidine chloride, etc.) and the high alcohol content of the wash buffers (~70-90% alcohol concentration); this waste cannot be disposed of in the sink.
  • Below is a diagram showing the proper setup for vaccuum flask aspiration.  Please click the image for a copy of the setup:

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Solid Waste


  • Solid biological waste includes plastic plates, petri dishes, paper towels, gloves, pipette tips, plastic serological pipettes, etc. that have been used with or come in contact with biological material
  • Collect all biologically contaminated solid waste in a benchtop waste transfer container, biohazard step can, or dispose directly in a biowaste box
    • Benchtop transfer containers: at the end of each day empty directly into a biowaste box
    • Step cans: once full, tie bags and dispose directly into biowaste box
  • When the biowaste box is approximately ¾ full:
    • Schedule pickup by completing Biological Waste Pickup Form online or through an Atlas request located under the EHS Waste Management tab or
    • Move the box to the collection area if your lab receives regularly scheduled pickup
    • Check with your EHS Representative to determine which method your lab uses
  • EHS will come out, collect the full boxes, and provide fresh biowaste boxes
  • Biowaste boxes are shipped off-site by a commercial vendor (Stericycle) for proper decontamination and disposal

Special considerations

  • Gloves used in a biological lab must be disposed of as biohazardous waste regardless of whether they were used with biological material; such gloves may not be disposed of in the regular trash (material in most boxes are used in waste-to-energy programs or hard plastic recycling; incinerate only boxes go to a properly constructed incinerator)
  • Liquids must not be disposed in the biowaste boxes: 
    • If the inner bags leak and the outer box gets wet, Stericycle will not pick-up the box and your lab will be responsible for decontaminating the box, separating the biological waste, and repacking everything it into new biowaste boxes
    • Residual liquids in a sealable container (5-10 ul or less) can be capped tightly and disposed of in the biowaste boxes
    • Plates with residual liquid (less than 10-20 ul per well) can be taped closed, placed in a Ziploc bag with absorbent material (paper towels) and disposed of in the biowaste box
    • For labs needing to dispose of multiple tubes of liquids less than 1 ml, these can be capped tightly, placed in a sealable plastic bag (such as a ziplock) that contains sufficient absorbent material (typically paper towels) to absorb the total volume of liquid contained in the tubes.
  • Anything that can easily puncture the outer box (such as razor blades, needles, glass pipettes, etc.) must go in a biosharps or puncture proof container; please see the Sharps Waste section below.
  • Animal carcasses and animal tissue cannot go in most biowaste boxes due to state regulations
    • Animal carcasses and tissue originating in DCM must be returned to DCM for proper disposal - please contact the DCM animal resource managers at 617-253-9434 for guidance or assistance
    • For all other animal carcasses or animal tissues, please contact BSP for guidance
  • Intact human tissue (including organs and bone) must be placed in placed into designated “incinerate-only” biowaste boxes which are completely incinerated; please contact BSP for arrangements
  • Please contact BSP for guidance on handling mixed hazardous chemical/biological solid waste and mixed radioactive/biological solid waste


  • EHS provides the following supplies free of charge:
    • Benchtop waste transfer containers
    • Biohazard step cans and step can liners
    • Biowaste boxes with coasters and lids
    • Biosharps containers
  • These can be requested in the comments section of the Biological Waste Pickup Form

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Sharp waste



  • Sharp waste includes needles & syringes, razor blades, glass slides, glass vials, and anything that can puncture the skin that has been used with or come into contact with biological material
  • Collect all biologically contaminated sharps in a puncture-resistant sharps container labeled with a biohazard sticker
  • When full, tightly seal the sharps container and dispose directly into a biowaste box
  • For broken glass too large for a standard bench-top sharps’ container (e.g. a broken 1 L flask):
    • Collect in a standard cardboard box
    • Close box, taped flaps shut, and placed directly into a biowaste box for disposal

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Autoclave Option


Solid waste:


 Liquid waste:


Labs that wish to routinely autoclave biological waste must have prior CAB/ESCRO (The Committee on Assessment of Biohazards and Embryonic Stem Cell Research Oversight) approval and have access to a designated, annually calibrated autoclave.

  • Only designated and calibrated autoclaves can be used to decontaminate biological waste
  • To autoclave solid waste:
    • Collect biologically contaminated, non-sharp solid waste in a clear autoclave bag which has no biohazard symbol/ markings
    • Clear autoclave bag should line an appropriate leakproof waste container marked with the universal biohazard symbol (such as EHS step-cans).
    • When the bag is full, place completed autoclave tag firmly on bag
      • The law requires tags to be attached to the waste bag
      • Tags are provided by EHS office
      • To request tags please send email to or call 2-3477
    • Leave bag OPEN during autoclaving - this allows effective steam penetration
    • Place waste bag with tag in a secondary, autoclave-proof container
    • Run solid waste cycle (121oC, 15 psi, 45-90+ minutes - large bags/volume may require 90 minutes or more)
    • Once run is complete:
      • Put on appropriate Personal Protective Equipment (PPE) - safety glasses, long sleeves or lab coat, and gloves rated for hot items
      • Check that chamber pressure gauge reads zero
      • Crack door to allow steam to release
      • Allow contents to cool at least 10 minutes
      • Open door slowly as waste will still be hot
      • Failure to allow sufficient cooling time and failure to use PPE may result in injury
    • Enter waste run in autoclave log binder which are usually located near the equipment
    • Documentation must include tag I.D. number (sequentially numbered)
    • Place treated and tagged waste bags into regular waste for custodial pickup
  • To autoclave liquid waste:
    • Liquids for sterilization must always be in a primary container
    • Place primary liquid containers in an appropriate autoclave tray - autoclave tray acts as secondary containment
    • If you choose to put water in the autoclave tray to facilitate the sterilization process, make sure the volumes are low since residual liquid in the autoclave tray post sterilization poses an increased risk of burns while removing your samples
    • Do not seal liquid waste containers; this will prevent the container from building up pressure and potentially exploding or liquid boiling over
    • Run a liquid sterilization cycle (121oC, 15 psi, 25 minutes per gallon of liquid)
      • Safety Note: if you run a solid sterilization cycle, the final exhaust step does not include a slow exhaust.  This will not allow enough exhaust time and liquids can boil over!
    • Once run is complete:
      • Put on appropriate Personal Protective Equipment (PPE) - safety glasses, long sleeves or lab coat, and gloves rated for hot items
      • Check that chamber pressure gauge reads zero
      • Crack door to allow steam to release
      • Allow contents to cool at least 10 minutes
      • Open door slowly as waste will still be hot
      • Failure to allow sufficient cooling time and failure to use PPE may result in injury
  • Sharps waste should not be autoclaved; please see the Sharps Waste section above or contact BSP for options
  • Web-based autoclave safety training is available; please see the Biosafety Specific Training webpage for details
    • Users must have lab-specific hands-on training on the autoclave they will operate
    • This is typically done by the lab EHS representative or designated experienced operator
  • All autoclaves on campus must be validated on a quarterly basis to ensure proper operation; please see the Autoclave Validation webpage for details

Autoclave supplies

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