HW – How to Collect and Label

Collect Your Waste
Label Your Waste
Dispose Your Waste

Proper collection, identification, and storage of hazardous waste are a critical functions of operating a safe lab space, whether it be a teaching or research lab.  Please follow the rules and procedures on this page.
Questions?  Contact the Chemical Hygiene Officer or your Stockroom Manager.


BEFORE You Start an Experiment:
STEP 1: Determine if Your Waste will be Hazardous
  • Go to the University of Minnesota online Chemical Waste Registry.
  • Type in either the Chemical Name or CAS Number (Chemical Abstract Services) and click on “Search.”
  • Look at DDC #.  In the Search Results, look under the “DDC #” column (for a review of the DDC system look here).
    • “xxNH” —  If the DDC contains two numbers followed by the letters “NH” (i.e., 05NH), then the substance generally is considered nonhazardous and can be disposed down the sewer or in the trash; however, please first consult with the CHO before placing anything in the trash or sewer.
    • If the DDC# includes anything except the “xxNH” designation, then assume that the waste is hazardous waste.
    • If your waste is a mixture of chemicals, and if one of the chemicals does not contain the “xxNH” designation, then assume that the combined substance is hazardous waste unless the CHO states otherwise.

STEP 2: Think about the Consequences of Your Waste (Quantity, Hazards, Compatibility)
  • Are you prepared to safely handle and store this waste until its removal?
  • STOP!!  Can You Mix Your Wastes?  Are they compatible?
  • Do you know how to respond to a spill?
  • Can you use alternative substances or change your procedure to either eliminate the creation (or reduce the amount) of hazardous waste, or create waste that has lower hazardous properties?

STEP 3: Obtain a HW Container (and Screw-top Lid), HW Sticker, and Log Sheet
  • HW Containers.
    • 20L and 4L containers (and screw-top lids) are available in RNS 341, on shelves near the elevator (if you take a container and lid then write this info on the stockroom check-out sheet that is hanging on the door).
    • Other sizes are available from the Stockroom Managers.
    • HW Container Lids
      • HW containers must have a screw-top lid; containers with corked lids, stoppers, parafilm, etc. are not acceptable.
      • If necessary place your corked/stopper container into a larger screw-top container.
      • Vented Lids.  If you suspect even the slightest buildup of gases within your HW container (e.g., you have used nitric acid), then obtain a vented lid from RNS 341.  There are vented lids for 20L and 4L containers.
    • IS YOUR HW CONTAINER CLEAN?  Be sure that the container that you plan to use for your waste has been rinsed completely of any previous substance to avoid the possibility of mixing incompatible chemicals.
    • Remove or deface (use a Sharpie marker) any old labels that may already be on the container.
    • Please contact the CHO if you have questions about your HW container.
  • HW Stickers are in RNS 253 or 341; affix it to the front of the HW container.
    Stickers are in RNS 253 & 341.
    Stickers are in RNS 253 & 341.
  • HW Log Sheets can be downloaded, or obtain one from RNS 253 or RNS 341 (the Google Doc version of the HW Log Sheet appears onscreen with unusual formatting; the downloaded doc will be formatted correctly).
  • Write the following information on both the HW Log Sheet AND the HW Sticker (These are critical steps as it allows us to match the container to the proper HW Log):
    • Start Date.
    • RNS room number.
    • On the HW Log Sheet, indicate the container size (20L, 4L, other) and the waste state (Solid or Liquid).

NITRIC AID – Use a Vented Lid; DO NOT MIX WITH Organic Solvents or Organic Acids
  • This video explains the hazards of mixing nitric acid with other wastes.
  • STOP!!  Can You Mix Your Wastes?  Are they compatible?
  • Do not mix Nitric Acid Waste with:
    • Acetic Acid; Acetic Anhydride; Acetone; Acetonitrile; Acrylonitrile; Alcohols; Aldehydes; Alkali Metals; Ammonia; Cyanides; Powdered Metals; other Organic Substances
  • “…Nitric Acid is the common chemical most frequently involved in reactive incidents, and this is a reflection of its exceptional ability to function as an effective oxidant even under fairly dilute conditions (unlike sulfuric acid) or at ambient temperature (unlike perchloric acid).  Its other notable ability to oxidize most organic compounds to gaseous carbon dioxide, coupled with its own reduction to gaseous ‘nitrous fume’ has been involved in many incidents in which closed, or nearly closed reaction vessels … have failed from internal gas pressure.”  (Bretherick 1990)
  • Use a Vented Lid.  If you do have Nitric Acid mixed with other substances, then you must use the vented screw-top lids that we have in stock in RNS 341.

DURING Your Experiment:
Update the HW Log Sheet every time Waste is Added

Warning: DO NOT MIX Nitric Acid with Organics!

If you have Nitric Acid Waste Then Read These Procedures.

  •  Fill out the HW Log Sheet. Use a separate column for each substance added to the container.  Each and every time that a substance is poured into the waste
    HW Jar & Log Sheet
    HW Container & Log Sheet

    container, you MUST print the following information onto the Hazardous Waste Log sheet:

    • Chemical name (complete spelling, no abbreviations).  For “pre-existing” mixtures you can indicate the ratio (e.g., Acetone:Water/3:1).
    • Quantity added (in ml or mg).
    • Your initials (your students must initialize if they pour substances into containers).
    • The lab section (if appropriate).
    • Note the presence of any sludge or precipitate.

Keep Container Closed (And Special Instructions for HPLC/Analytical Waste Containers)
  • The container must remain closed at all times, except for those very brief seconds when waste is actually being poured into the container.
    • If the container has a screw-on funnel with a close-top lid, then close the lid.
    • If you use a removable funnel, then you must remove the funnel and screw on the cap.
  • HPLC and Other Analytical Waste Containers.  HPLC and other such liquid waste is generated slowly and over an extended period of time when the equipment is used as intended, and it is not practical to open and close the waste container during the analytical process.  Furthermore, the container cap needs to be vented.
    • The container cap must have at least two holes in it; one for the HPLC hose and the other to vent the container.  The holes should be of such a diameter that the hose fits snugly into the cap and the vent hole is only large enough to prevent pressure build-up while the container is being filled.  These vented caps can be transferred to the container being filled and the full container can be capped with an unmodified cover.
      • Contact the CHO or StockroomManager to obtain these vented caps.
    • Practices that ARE NOT acceptable include wrapping hoses with tin foil, tissue, rubber gloves, tape, wax, or other loosely-fitted materials.  These methods do not meet the regulatory requirements and are considered open containers by the regulatory authorities.

Neutralize the Mixture, if Possible
  • Neutralize the Mixture, if Possible – It Saves Us Money. Disposal of corrosive wastes are substantially more expensive than the neutralized version of the same wastes; therefore, please neutralize your waste if it is feasible.  In fact, once neutralization has been completed, the substance may not qualify as waste and it might be permissible to pour it down the sink.  Please check first with the CHO.  “Neutralize” in this case means a pH between 5-9; the pH does not need to be 7.

AFTER Your Experiment (or when the Container is Ready for Removal):
  • Inform your Stockroom Manager or the CHO, who will remove the container.
  • IMPORTANT: If you will need a new container then please inform the Stockroom Manager before your waste container is completely full.  This will ensure that a new container is brought to the lab in time.

  • Neutralize the Mixture, if Possible – It Saves Us Money. Disposal of corrosive wastes are substantially more expensive than the neutralized version of the same wastes; therefore, please neutralize your waste if it is feasible.  In fact, once neutralization has been completed, the substance may not qualify as waste and it might be permissible to pour it down the sink.  Please check first with the CHO.
    • Option 1: Neutralize the waste before pouring it into the waste container.
    • Option 2: Neutralize the mixture in the container on a set interval (e.g., at the end of each lab period, or after adding x-amount of waste to the container).  Be alert to the generation of heat.
    • Option 3: Neutralize the final mixture in the container once the container is full/no longer being filled.  Be alert to the generation of heat.
    • Neutralize” in this case means a pH between 5-9; the pH does not need to be 7.  Be alert to the generation of heat.
  • Record the final container pH on the Hazardous Waste Log Sheet.
  • Record the total quantity (ml or mg) of each waste constituent in the container (sum the columns).
  • Removal of Container from Your Lab.  
    • Inform the CHO, who will remove the container, or
    • You may bring your waste container and HW Log Sheet to RNS 253, 341, or 441.   There are designated locations for different types of waste (liquids, solids, sharps, electronics, batteries):
      • RNS 341: shelves near the elevator.
      • RNS 253/441: in the fume hood.
    • Remove all waste containers from your lab at least once per year, even if the container is not full.



Pure Chemicals or a Commercial Product

Pure Chemicals are outdated or excess chemicals that you no longer need.  Commercial Chemicals include old paints, aerosols, glues, etc., that you might purchase from Menards or other such suppliers (online or in person).

  • Write the following information on the HW Log:
    • On the “Room Location” line; include the Room Number & Faculty member’s name.
    • End Date.
    • pH (if applicable).
    • For a Pure Chemical: write down the substance name and (if applicable) concentration in the first column.
    • For a Commercial Chemical: please provide the product name and manufacturer information (company name & address, etc.).  You can write this information in the empty column headings or along the bottom of the sheet.
    • Amount.

If You Have a True Unknown Chemical
  • Download the “Procedures for Unknowns” worksheet and perform as many steps as feasible.
  • Bring the completed worksheet and container to RNS 341.
    • The substance will be handled as an unknown or “limited known” and labeled accordingly by the CHO.
    • Disposal costs will surely be higher than if we had a known list of ingredients; therefore, it is imperative that faculty always keep track of their containers and eliminate the production of “unknowns.”