Table III-1 EPA Compatibility Table

Table III-1. Environmental Protection Agency (EPA) Compatibility Table

EPA has published a list of potentially incompatible wastes, waste components and materials 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.

For example, mixing any Group 2-A waste, which include reactive metals and metal hydrides, with a Group 2-B waste, which include the Group 1-A alkaline and the Group 1-B acidic wastes, may produce a fire or explosion and the generation of flammable hydrogen gas. Mixing a Group 3-A waste, which includes alcohol’s and water, with a Group 3-B waste, which encompass Groups 1-A, 1-B and Group 3-B listed chemicals, may produce a fire, explosion or heat and the generation of flammable or toxic gases.

These compatibility listings and packaging guides should not be the only information used when packaging or accumulating waste chemicals. RCRA regulations require that wastes should be adequately analyzed by TSD facilities so uncontrolled substances or reactions do not occur. Pay close attention to any waste characterization data you receive on material reactivity and compatibility. There are also other sources of data that may be helpful in determining waste compatibility. SDS’s contain a section devoted to chemical reactivity and incompatibility. The National Fire Protection Association (NFPA) publishes a manual of hazardous chemical reactions which contains over 3,500 documented dangerous chemical reactions.


Group 1-A

Group 1-B

Acetylene sludge

Acid sludge

Alkaline caustic liquids

Acid and water

Alkaline cleaner

Battery acid

Alkaline corrosive liquids

Chemical cleaners

Alkaline corrosive battery fluids

Electrolyte, acid

Caustic wastewater

Etching acid liquid or solvent

Lime sludge and other corrosive alkalies

Pickling liquor and other corrosive acids

Lime wastewater

Spent acid

Lime and water

Spent mixed acid

Spent caustic

Spent sulphuric acid

Potential consequences: Heat generation; violent reaction.

Group 2-A    







Zinc powder


 Other reactive metals and metal hydrides

Group 2-B    

Any waste in Group 1-A or 1-B

Potential consequences: Fire or explosion; generation of flammable hydrogen gas.

Group 3-A

Group 3-B


Any concentrated waste in Groups 1-A or 1-B






Metal Hydrides




SO2Cl2, SOCl2, PCl3, CH2SiCl2


Other water-reactive waste

Potential consequences: Fire, explosion, or heat generation; generation of flammable or toxic gases.

Group 4-A

Group 4-B


Concentrated Group 1-A or 1-B wastes


Group 2-A wastes

Halogenated hydrocarbons


Nitrated hydrocarbons


Unsaturated hydrocarbons


Other reactive organic compounds and solvents


Potential consequences: Fire, explosion or violent reaction.

Group 5-A

Group 5-B

Spent cyanide and sulfide solutions Group

1-B wastes

Potential consequences: Generation of toxic hydrogen cyanide or hydrogen sulfide gas.

Group 6-A

Group 6-B


Concentrated mineral acids


Group 2-A wastes


Group 4-A wastes

Chromic acid

Other flammable and combustible wastes





Nitric acid, fuming








Other strong oxidizers


Acetic acid and other organic acids


Potential consequences: Fire, explosion, or violent reaction.

Source: 40 CFR 264, Appendix V.