Hazardous Waste Management Manual - Unknown and Orphaned Chemical Waste

Unknown Wastes

Every effort must be made to provide an accurate description of all hazardous chemical wastes given to EHS&RM for handling and disposal. 

Unknown waste will be accepted by EHS&RM, but there will be a $50 waste identification / characterization charge for each unknown chemical container turned into EHS&RM for disposal. 

Hazardous waste disposal companies will not accept waste without proper waste characterization analysis, EH&S will complete a fingerprint analysis in attempt to identify the unknown. If further analysis is required, EH&S will notify the department. However; it is preferred that the generator (individual or department) to accurately identify all chemical unknowns in their laboratory, either by knowledge or analysis.

Take Steps to Identify Unknown Wastes

The process of identifying an unknown chemical can be tedious and paying for a commercial analysis can be cost prohibitive. However, some things can be done to help identify a waste prior to turning it into EHS&RM as an unknown.

  • Ask other personnel (present and past) if they have any information that may help to identify the waste.
  • Conduct simple chemical and physical tests to narrow the unknown down to broad chemical categories such as organic or inorganic. Consult with knowledgeable faculty, staff or EHS&RM prior to testing, if necessary.
  • Exercise caution in opening containers containing unknown substances, especially if the cap is corroded or disfigured. If unsure, seek assistance before opening.

Orphaned Chemicals - Left-Overs’ :

Like unknown chemicals, laboratory glassware containing reaction mixtures of an unknown nature and sometimes of unknown origin, can present difficult handling and disposal problems. Such materials occur frequently in research laboratories, particularly in those that have a high rate of personnel turnover.

Knowledge of the chemistry that was being conducted by the departed laboratory worker might provide a clue as to the identity of the mixture. The identification of such compounds can be achieved in primarily the same way as unknown chemicals.


The following suggestions will assist in reducing problems associated with unknown wastes and orphan chemicals:

  • Label all secondary chemical containers. Replace defaced labels with new ones.
  • Institute a periodic review of chemical stock and rotate stock as new chemicals are purchased.
  • Maintain accurate records of chemicals in stock. This will help in the identification of any containers with missing labels.
  • Require all reaction mixtures stored in laboratory glassware to be labeled with the chemical composition, the date they were formed, the name of the laboratory worker responsible and a notebook reference. This procedure can provide the information necessary to facilitate the disposal of the mixture if the responsible laboratory worker is not available.
  • Use a check-out procedure that requires departing laboratory personnel to identify any remaining reaction mixtures and to provide information necessary for safe disposal. It may be necessary to require a financial deposit from incoming graduate students. This deposit would be refunded at the time of their departure once it has been determined that no orphaned mixtures have been left behind, all unknown chemicals have been identified and all waste chemicals have been properly removed from the laboratory.
  • Set a procedure that requires in-coming faculty, researchers, graduate students and others using laboratory space to check their new location prior to starting work for any orphan reaction mixtures or unknown chemicals that may be present.
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