Request for Information on Test Methods for Evaluating Solid Waste, Waste Sampling and Toxicity Characteristic Leaching Procedure Testing

On September 14, 2026, EPA published a Request for Information seeking public input on updates to test methods and waste sampling guidance under the Resource Conservation and Recovery Act. Through this RFI, EPA is asking interested parties to share their experience using the Test Methods for Evaluating Solid Waste, including challenges, needs, and possible improvements. 

EPA is specifically interested in feedback on the Toxicity Characteristic Leaching Procedure Method 1311, including any issues with the method and possible alternatives. EPA welcomes input from industry, researchers, academia, state, Tribal and local governments, U.S. territories, the District of Columbia, other federal agencies, community groups, non-governmental organizations, the public, and international organizations. 

The Test Methods for Evaluating Solid Waste: Physical/Chemical Methods, also known as the SW-846 Compendium or simply SW-846, is EPA’s official collection of test methods and guidance recommended for use in in conducting the evaluations and measurements needed to comply with the Resource Conservation and Recovery Act, Public Law 94-580, as amended. SW-846 methods are approved by the U.S. Environmental Protection Agency for obtaining data to satisfy the requirements of 40 Code of Federal Regulations Parts 122 through 270 promulgated under RCRA, as amended.  

SW-846 methods are organized in series to address different topics or classes of chemicals. The SW-846 contains procedures for field and laboratory quality control, sampling, determining hazardous constituents in waste, determining the hazardous characteristics of waste (toxicity, ignitability, reactivity, and corrosivity), and for determining physical properties of waste. It also contains guidance on how to select appropriate methods.  The SW-846 Compendium was first published in 1980, and it is a “living document” in that the methods and chapters are expanded and updated over time to keep up with evolving analytical instrumentation, quality assurance practices and measurement needs. 

Several of the hazardous waste regulations under Subtitle C of RCRA require that specific testing methods described in SW­-846 be employed for certain applications. Refer to 40 CFR Parts 260 through 270, for those specific requirements. Any reliable analytical method may be used to meet other requirements under Subtitle C of RCRA.  

The Agency uses the TCLP to estimate the potential for waste to leach hazardous constituents to groundwater, where they may be transported to a drinking water well, which may in turn result in human exposure to the toxic constituent. TCLP is designed to reflect conditions likely to occur in a municipal solid waste landfill, as the Agency identified industrial waste co-disposal in an MSW landfill as plausible management for unregulated waste. 

In 1980, prior to development of the TCLP, the Agency adopted the Extraction Procedure to identify waste likely to leach hazardous concentrations of particular toxic constituents into the groundwater under conditions of improper management (45 FR 33110, May 19, 1980 (pdf)(185 MB)). In 1986, the Agency proposed a modified leaching procedure, the TCLP, to replace the EP (51 FR 21648, June 13, 1986 (pdf)(59 MB)). The Agency promulgated the final rule on the application of the TCLP in 1990 (55 FR 11827, March 29, 1990 (pdf)(18.2 MB)). 

In 1991 and 1999, the Science Advisory Board reviewed the Agency’s leaching evaluation methodology and expressed concern about the widespread non-regulatory use of TCLP, including for estimating leaching under conditions that are substantially different from the conditions built into TCLP (such as contaminated sites). The SAB recommended that EPA develop a new, flexible methodology to better represent aqueous leaching under the range of conditions to which the waste will be exposed after disposal. 

In response, EPA developed the Leaching Environmental Assessment Framework methods to better model chemical release from waste and contaminated source areas under a range of site-specific conditions or management scenarios. More information is available on our Leaching Environmental Assessment Framework Methods and Guidance webpage.