EPA has revised its procedures for making certain changes to its “Test Methods for Evaluating Solid Waste, Physical/Chemical Methods,” also known as SW-846. The test method and its compendium of guidance documents provide over 200 analytical methods for sampling and analysis of waste and other matrices. Most methods are intended as guidance, but others are required in the RCRA regulations for compliance purposes. Periodically, EPA amends or adds analytical protocols to SW-846 based on public comments or professional developments, and historically the changes have been published in the Federal Register for public review and comment.