Unknown Chemical(s) Guidance

An unknown is defined as a chemical in an unlabeled container for which the identity is undetermined.  Federal, state, and local regulations all specifically prohibit the transportation, storage, or disposal of unknown wastes. In addition, hazardous waste disposal companies will not accept unknowns without proper analysis. Therefore, unknown or unlabeled chemicals all require analysis prior to disposal, which can easily cost $1,000 or more for a single sample.  Unknown chemicals present serious legal and safety problems for the University.

  • Preventing Unknown Chemicals

    Many unknown chemicals are generated due to a lack of good housekeeping and good laboratory safety practices. Unknown and unlabeled chemicals can be prevented by:

    • Labeling all containers (including beakers and test tubes) properly. This should be done even when creating reagent solutions for temporary use. Labeling will also prevent using the wrong material accidentally.
    • Inspecting containers and labels in the lab inventory periodically and replacing fading or deteriorating labels that are not legible.
    • Labeling containers using full chemical names, not abbreviations, chemical structures, or formulas.
    • Archived research samples are often stored in boxes containing hundreds of small vials. Label the outside of the box with the chemical constituents, paying special attention to regulated materials such as radioactives, solvents, heavy metals, and other toxic materials. If the samples are nonhazardous, label them as such.
    • Maintaining an accurate chemical inventory list.
    • Require all reaction mixtures stored in lab glassware to be labeled with chemical composition, the date they were formed, and the name of the lab worker responsible.
    • Require all workers to properly identify any unknown materials before they leave the area or lab.
    • In the event of lab staff turnover or graduation, require all materials be identified and dispose of all materials and samples that are no longer in use or wanted.
    • Submit frequent waste pick up request forms to reduce the amount of hazards in your laboratory to reduce risk and create more lab space.
  • Identifying Unknown Materials

    Every effort should be made to properly identify an unknown chemical prior to contacting EHS. The following steps should be taken to help identify unknown and unlabeled chemicals:

    • Consult with the Principal Investigator (PI) or Lab Manager about the type of work that was being conducted. Eliminating certain chemicals as a possibility helps narrow down the determination and also helps with final waste disposal. This is especially important for materials that may contain mercury, polychlorinated biphenyls (PCBs), polyfluoroalkyl substances (PFAS), dioxins, and furans, as they require special handling for disposal.
    • Ask area personnel about the container.
    • Contact groups that previously used that area and see if they can provide any information on the identity of the materials.
    • Review projects current in process.
  • Disposal of Unknown Materials

    If the identity of the material cannot be determined through all of the steps identified above, EHS will remove the material and dispose of it. However, EHS requires three tests be performed and the results recorded on the hazardous waste tag prior to pick up. EHS will not remove any wastes for disposal without a properly filled out hazardous waste tag on the container, or a properly submitted Hazardous Waste Request in the Safety Portal. In addition, based on the number of unknowns in a lab, EHS may charge the generator or department a fee per bottle for the analysis and identification of the waste.

    Visually evaluate the material, if the container is swollen, compromised, damaged or compromised, or shows visible evidence of crystal growth within the container, contact EHS immediately.

Unknown Testing Procedures 

All tests performed should be conducted in a functioning fume hood. Use as small a sample as reasonably possible while performing the tests. The results of each test should be noted on the hazardous waste tag prior to pick up by EHS.

  • Test 1: Flammability

    When performing flame tests with liquids, use cotton tipped applicators to dip into the liquid before igniting.

    When performing the flame tests with solids, use a spatula to obtain a very small amount of the sample to minimize potential reactions.

  • Test 2: pH
    Coming soon
  • Test 3: Water Miscibility

    Use as small a sample as reasonably possible while adding the material to water rather than adding water to the sample.