{"data":{"id":"us/40-cfr-appendix-v-to-part-264","jurisdiction":"us","citation":"40 CFR Appendix V to Part 264","heading":"Appendix V to Part 264—Examples of Potentially Incompatible Waste","body":"Many hazardous wastes, when mixed with other waste or materials at a hazardous waste facility, can produce effects which are harmful to human health and the environment, such as (1) heat or pressure, (2) fire or explosion, (3) violent reaction, (4) toxic dusts, mists, fumes, or gases, or (5) flammable fumes or gases.\nBelow are examples of potentially incompatible wastes, waste components, and materials, along with the harmful consequences which result from mixing materials in one group with materials in another group. The list is intended as a guide to owners or operators of treatment, storage, and disposal facilities, and to enforcement and permit granting officials, to indicate the need for special precautions when managing these potentially incompatible waste materials or components.\nThis list is not intended to be exhaustive. An owner or operator must, as the regulations require, adequately analyze his wastes so that he can avoid creating uncontrolled substances or reactions of the type listed below, whether they are listed below or not.\nIt is possible for potentially incompatible wastes to be mixed in a way that precludes a reaction (e.g., adding acid to water rather than water to acid) or that neutralizes them (e.g., a strong acid mixed with a strong base), or that controls substances produced (e.g., by generating flammable gases in a closed tank equipped so that ignition cannot occur, and burning the gases in an incinerator).\nIn the lists below, the mixing of a Group A material with a Group B material may have the potential consequence as noted.\nGroup 1-A\nAcetylene sludge\nAlkaline caustic liquids\nAlkaline cleaner\nAlkaline corrosive liquids\nAlkaline corrosive battery fluid\nCaustic wastewater\nLime sludge and other corrosive alkalies\nLime wastewater\nLime and water\nSpent caustic\nGroup 1-B\nAcid sludge\nAcid and water\nBattery acid\nChemical cleaners\nElectrolyte, acid\nEtching acid liquid or solvent\nPickling liquor and other corrosive acids\nSpent acid\nSpent mixed acid\nSpent sulfuric acid\nPotential consequences: Heat generation; violent reaction.\nGroup 2-A\nAluminum\nBeryllium\nCalcium\nLithium\nMagnesium\nPotassium\nSodium\nZinc powder\nOther reactive metals and metal hydrides\nGroup 2-B\nAny waste in Group 1-A or\n1-B\nPotential consequences: Fire or explosion; generation of flammable hydrogen gas.\nGroup 3-A\nAlcohols\nWater\nGroup 3-B\nAny concentrated waste in Groups 1-A or 1-B\nCalcium\nLithium\nMetal hydrides\nPotassium\nSO2 Cl2, SOCl2, PCl3, CH3 SiCl3\nOther water-reactive waste\nPotential consequences: Fire, explosion, or heat generation; generation of flammable or toxic gases.\nGroup 4-A\nAlcohols\nAldehydes\nHalogenated hydrocarbons\nNitrated hydrocarbons\nUnsaturated hydrocarbons\nOther reactive organic compounds and solvents\nGroup 4-B\nConcentrated Group 1-A or 1-B wastes\nGroup 2-A wastes\nPotential consequences: Fire, explosion, or violent reaction.\nGroup 5-A\nSpent cyanide and sulfide solutions\nGroup 5-B\nGroup 1-B wastes\nPotential consequences: Generation of toxic hydrogen cyanide or hydrogen sulfide gas.\nGroup 6-A\nChlorates\nChlorine\nChlorites\nChromic acid\nHypochlorites\nNitrates\nNitric acid, fuming\nPerchlorates\nPermanganates\nPeroxides\nOther strong oxidizers\nGroup 6-B\nAcetic acid and other organic acids\nConcentrated mineral acids\nGroup 2-A wastes\nGroup 4-A wastes\nOther flammable and combustible wastes\nPotential consequences: Fire, explosion, or violent reaction.\nSource: “Law, Regulations, and Guidelines for Handling of Hazardous Waste.” California Department of Health, February 1975.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER I—SOLID WASTES","PART 264—STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"31c4858fbf091a6023b0cc81c714efb5f0e4fb9fa1a8ca234fd1d03b944d3cfb","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-appendix-iv-to-part-264","next":"us/40-cfr-appendix-vi-to-part-264"},"notice":"GroundRules: Original legal text. Not legal advice."}