United States Environmental Protection Agency
Washington, D.C. 20460
Office of Solid Waste and Emergency Response

October 5, 1989

Mr. Travis P. Wagner
Labat-Anderson Incorporated
2200 Clarendon Boulevard, Suite 900
Arlington, Virginia 22201

Dear Mr. Wagner:

     I am writing in response to your letter requesting written clarification of the Resource Conservation and Recovery Act (RCRA) definition of a liquid as it applies to ignitable and corrosive wastes.

     There are three RCRA definitions which include the term "liquid". The definitions vary depending on the specific regulatory application. For hazardous waste identification by means of the three relevant characteristics (Ignitability, Corrosivity or Extraction Procedure Toxicity), the general term liquid applies. "Liquid" is defined as the material (liquid phase) that is expressed from the waste in Step 2 of Method 1310 (the Extraction

     As Mr. Friedman indicated, only those wastes that contain a liquid component are subject to testing against the flash point criteria of Section 261.21. Therefore, if a waste does not yield a liquid phase when subjected to Method 1310, it cannot be an ignitable waste under the criteria of Section 261.21(a)(1).

     Similarly, Section 261.22(a)(2) states that a liquid waste is a corrosive waste if it exhibits a pH less than or equal to 2 or greater than or equal to 12.5. If a waste does not yield a liquid when subjected to Method 1310, it is not evaluated against this criteria and is not a corrosive waste.

     A second definition of liquids which is applied to determine whether a drummed waste is prohibited from land disposal because it contains "free liquid", is found in Method 9095 (the Paint Filter Test). If any material drips from the filter during the test, the waste is deemed to contain "free liquid" and is banned from land

     Many people have used the Paint Filter Test to evaluate wastes for ignitability or corrosivity. This is done to save time and effort. Since liquids that separate out of the waste using Method 9095 are generally also liquids using Method 1310 wastes that contain ignitable or corrosive liquids using Method 5 can generally be considered to be ignitable or corrosive wastes.

     The third definition of liquids was developed when the 1984 amendments to RCRA prohibited the use of adsorbents to solidify liquid wastes if the adsorbents would release the contained liquids under landfill pressures. Prohibited adsorbents are those that contain "releasable liquids". While the Agency has not yet promulgated a specific test procedure for defining when a waste contains "releasable liquid", a draft procedure has been developed and proposed - Method 9096 (the Liquid Release Test).

     I trust that this explanation clarifies the RCRA definitions. Please contact us if you need further assistance.
Sylvia R. Lowrance
Office of Solid Waste