The proper segregation of waste chemicals is essential to promote safe storage of those chemicals as well as to facilitate the economical disposal of the chemicals. The Environmental Protection Agency (EPA) has published a list of potentially incompatible wastes, waste components, and material along with the harmful consequences of mixing those materials together. This list does not include every possible hazardous chemical reaction, but should be used as a guide in packaging and storing these materials. The list indicates the potential consequences of the mixing of a Group A material with a Group B material. These compatibility listings should not be the only information used when packaging or accumulating waste chemicals. Pay close attention to any waste characterization data you receive on material reactivity and compatibility. Material Safety Data Sheets contain a section devoted to chemical reactivity and incompatibility. The following lists of chemicals in Groups A should be kept separate from those chemicals in Groups B:

Group 1-A	Group 1-B
Bases Potential consequences: Heat generation; violent reaction	Acids
Group 2-A	Group 2-B
Aluminum Beryllium Calcium Lithium Magnesium Potassium Sodium Zinc powder Other reactive metals and metal hydrides Potential consequences: Fire, Explosion, or generation of flammable hydrogen gas.	Any Acid or Bases
Group 3-A	Group 3-B
Alcohols Water Potential consequences: Fire, Explosion, or heat generation: generation of flammable or toxic gases.	Any Concentrated Acids or Bases Calcium Lithium Magnesium Sodium Zinc Powder Any Reactive Metals and Metal Hydrides Potassium Sulfonyl chloride Thionyl chloride Phosphorus trichloride Methyl trichloride Methyl trichlorosilane Other water-reactive waste
Group 4-A	Group 4-B
Alcohols Aldehydes Halogenated hydrocarbons Nitrated hydrocarbons Unsaturated hydrocarbons Other organic compounds and solvents Potential consequences: Fire, Explosion, or violent reaction.	Any Concentrated Acids or Basses Reactive Metals and Metal Hydrides
Group 5-A	Group 5-B
Cyanide's and sulfide's Potential consequences: Generation of toxic hydrogen cyanide or hydrogen sulfide gas.	Any Acids
Group 6-A	Group 6-B
Chlorates Chlorine Chlorites chromic acid Hypochlorites Nitrates Nitric acid, fuming Perchlorates Permanganates Peroxides Other strong oxidizers Potential consequences: Fire, Explosion, or violent reaction.	Acetic acid and other organic acids Concentrated mineral acids Reactive Metals and Metal Hydrides Organic Compounds and Solvents Other flammable and combustible chemicals
The following two groups are added to facilitate the economical disposal of the wastes. They are not necessarily reactive.
Group 7-A	Group 7-B
Heavy metal Compounds containing arsenic, barium, cadmium, chromium, lead, selenium, silver Polychorlinated biphenyls (PCBs) Dioxins Mercury Containing Compounds	Flammable Liquids
Group 8-A	Group 8-B
Plychlorinated biphenyls (PCBs) Dioxins Mercury Containing Compounds	All other chemicals and each other