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Waste Designation Decision Matrix - P and U Listed Wastes

This is the waste designation decision matrix provided by the Small Business and Local Government Assistance Program to aid businesses in deciding how certain wastes must be handled.

This matrix is provided as an assistance tool. It cannot be used as a substitute for following applicable city, state, and federal laws.


The EPA has identified more than 400 chemicals that, in pure form, are "hazardous." These wastes are designated by either a "P" or a "U" followed by a 3-digit code, for example, P120 or U203. The P list includes "acutely hazardous wastes" that are considered especially harmful even in small quantities, such as cyanides. Most businesses rarely generate acutely hazardous waste. U-listed wastes are hazardous, although not acutely so; this group includes such common compounds as acetone.

P and U wastes are actually products that may have exceeded their shelf life that can no longer be used for their intended purpose. Thus, you generate hazardous waste if you discard an unused P or U listed chemical or an unused product whose sole active ingredient is a P or U listed chemical without using it. On the other hand, since P and U wastes comes from chemicals that have never been used, the P/U code is no longer applicable once a chemical has been used for its intended purpose.

Check the P list.      Check the U list.

Make a note of the appropriate code for the waste you have for use later in the decision matrix.

To determine if additional waste codes apply