Stanford University

Chemical Waste Disposal

Hazardous waste is a waste or combination of wastes whose quantity, concentration, or physical/chemical characteristics may pose a substantial present or potential threat to human health or the environment when improperly treated, stored, disposed of, transported, or otherwise managed.


General waste management practices

  • All faculty, students, and staff who generate hazardous waste must complete the “Chemical Safety for Laboratories” training course (EHS-1900).
  • Read more about the Chemical Waste Pickup services.
  • Access the online hazardous Waste Tag system.
  • All lab wastes containing chemical constituents are presumed by the State of California to be regulated hazardous wastes.
    • EH&S has determined that certain dilute mixtures are not hazardous wastes. See the Non-Hazardous Chemical Wastes.
    • If, due to your own knowledge and experience, you believe your waste may be non-hazardous, but it is not on the list, contact EH&S for a waste determination.
  • Reagent chemical containers that are in good condition and have a readable original manufacturer’s label are considered surplus chemicals. Lab personnel must affix a surplus sticker before requesting pickup by EH&S, but do not need a hazardous waste tag.
  • Do not dispose of hazardous chemicals or solutions containing hazardous chemicals in any sink or floor drain. Aqueous solutions containing only acids or bases and no toxic metals may be disposed in the drain if the pH is greater than 5.5 and less than 11.0. The first rinseate from chemically contaminated glassware must be collected as hazardous waste. Subsequent rinseates may be disposed of in the drain.
  • Do not dispose of any hazardous materials in the solid waste containers (e.g. trash cans or dumpsters) that go to the landfill.
  • Chemical waste must be under the control of the person generating the waste at all times, and must not be stored in general traffic locations, such as halls, or other areas with general public access.
  • Common areas may be used for collection of laboratory hazardous waste under the following restrictions:
    • No maintenance or other non-lab waste may be accumulated.
    • No more than 55 gallons may be accumulated.
    • The area must be as close as practical to the waste-generating locations.
    • Access must be restricted to trained and authorized personnel.

Segregating wastes

Accumulating waste

  • Do not accumulate waste containers in the lab for more than nine months.
  • Waste containers must be chemically compatible with the waste.
  • Always keep containers tightly closed, except when transferring waste. If using a funnel, it must be removed and replaced with a tight-fitting lid as soon as you have finished adding the waste.
  • All wastes must be secondarily-contained while in storage.
  • Unless you have established a “Waste Accumulation Area” through EH&S, never accumulate more than 55 gallons of chemical waste at any time.
  • EH&S provides 1-gallon, 3-gallon, and 5-gallon poly containers free of charge, upon phone request (x5-7520).

Labelling waste

  • Waste containers must be labeled when waste starts accumulating (i.e. as soon as the first drop of waste is put in the container), not when the container becomes full.
    • Reaction residues become wastes as soon as they are removed from the experimental equipment.
    • Samples and working solutions become wastes when they are no longer needed. Lab personnel make this determination.
  • Label all chemical waste containers using the online Stanford Hazardous Waste Tag system.
    • List all constituents, including water.
    • Do not use abbreviations or chemical formulas. If using a trade name, you must have a safety data sheet (SDS) for the material available.
    • Estimate the concentration of each constituent.

Submitting a request

  • A waste pickup request must be submitted once a waste container is eight months old, or becomes full, whichever occurs sooner.
  • Submit a pickup request using the online system.

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