When certain hazardous chemicals are stored or mixed together, violent reactions may occur because the chemicals are unsuitable for mixing, or are incompatible. Classes of incompatible chemicals should be segregated from each other during storage, according to hazard class. Use the following general guidelines for hazard class storage:

1. Flammable/Combustible Liquids and Organic Acids
2. Flammable Solids
3. Mineral Acids
4. Caustics
5. Oxidizers
6. Perchloric Acid
7. Compressed Gases

Before mixing any chemicals, refer to this partial list, the chemicals' MSDS, or contact the Chemical Hygiene Officer to verify compatibility:

CHEMICAL INCOMPATIBLE CHEMICAL(S)
Acetic acid aldehyde, bases, carbonates, hydroxides, metals, oxidizers, peroxides, phosphates, xylene
Acetylene halogens (chlorine, fluorine, etc.), mercury, potassium, oxidizers, silver
Acetone acids, amines, oxidizers, plastics
Alkali and alkaline earth metals acids, chromium, ethylene, halogens, hydrogen, mercury, nitrogen, oxidizers, plastics, sodium chloride, sulfur
Ammonia acids, aldehydes, amides, halogens, heavy metals, oxidizers, plastics, sulfur
Ammonium nitrate acids, alkalis, chloride salts, combustible materials, metals, organic materials, phosphorous, reducing agents, urea
Aniline acids, aluminum, dibenzoyl peroxide, oxidizers, plastics
Azides acids, heavy metals, oxidizers
Bromine acetaldehyde, alcohols, alkalis, amines, combustible materials, ethylene, fluorine, hydrogen, ketones (acetone, carbonyls, etc.), metals, sulfur
Calcium oxide acids, ethanol, fluorine, organic materials
Carbon (activated) alkali metals, calcium hypochlorite, halogens, oxidizers
Carbon tetrachloride benzoyl peroxide, ethylene, fluorine, metals, oxygen, plastics, silanes
Chlorates powdered metals, sulfur, finely divided organic or combustible materials
Chromic acid acetone, alcohols, alkalis, ammonia, bases
Chromium trioxide benzene, combustible materials, hydrocarbons, metals, organic materials, phosphorous, plastics
Chlorine alcohol's, ammonia, benzene, combustible materials, flammable compounds (hydrazine), hydrocarbons (acetylene, ethylene, etc.), hydrogen peroxide, iodine, metals, nitrogen, oxygen, sodium hydroxide
Chlorine dioxide hydrogen, mercury, organic materials, phosphorous, potassium hydroxide, sulfur
Copper calcium, hydrocarbons, oxidizers
Hydroperoxide reducing agents
Cyanides acids, alkaloids, aluminum, iodine, oxidizers, strong bases
Flammable liquids ammonium nitrate, chromic acid, hydrogen peroxide, nitric acid, sodium peroxide, halogens
Fluorine alcohol's, aldehydes, ammonia, combustible materials, halocarbons, halogens, hydrocarbons, ketones, metals, organic acids
Hydrocarbons (Such as butane, propane benzene, turpentine, etc.) acids, bases, oxidizers, plastics
Hydrofluoric acid metals, organic materials, plastics, silica (glass), (anhydrous) sodium
Hydrogen peroxide acetylaldehyde, acetic acid, acetone, alcohol's carboxylic acid, combustible materials, metals, nitric acid, organic compounds, phosphorous, sulfuric acid, sodium, aniline
Hydrogen sulfide acetylaldehyde, metals, oxidizers, sodium
Hypochlorites acids, activated carbon
Iodine acetylaldehyde, acetylene, ammonia, metals, sodium
Mercury acetylene, aluminum, amines, ammonia, calcium, fulminic acid, lithium, oxidizers, sodium
Nitrates acids, nitrites, metals, sulfur, sulfuric acid
Nitric acid acetic acid, acetonitrile, alcohol's, amines, (concentrated) ammonia, aniline, bases, benzene, cumene, formic acid, ketones, metals, organic materials, plastics, sodium, toluene
Oxalic acid oxidizers, silver, sodium chlorite
Oxygen acetaldehyde, secondary alcohol's, alkalis and alkalines, ammonia, carbon monoxide, combustible materials, ethers, flammable materials, hydrocarbons, metals, phosphorous, polymers
Perchloric acid acetic acid, alcohols, aniline, combustible materials, dehydrating agents, ethyl benzene, hydriotic acid, hydrochloric acid, iodides, ketones, organic material, oxidizers, pyridine
Peroxides, organic acids (organic or mineral)
Phosphorus (white) oxygen (pure and in air), alkalis
Potassium acetylene, acids, alcohols, halogens, hydrazine, mercury, oxidizers, selenium, sulfur
Potassium chlorate acids, ammonia, combustible materials, fluorine, hydrocarbons, metals, organic materials, sugars
Potassium perchlorate (also see chlorates) alcohols, combustible materials, fluorine, hydrazine, metals, organic matter, reducing agents, sulfuric acid
Potassium permanganate benzaldehyde, ethylene glycol, glycerol, sulfuric acid
Silver acetylene, ammonia, oxidizers, ozonides, peroxyformic acid
Sodium acids, hydrazine, metals, oxidizers, water
Sodium nitrate acetic anhydride, acids, metals, organic matter, peroxyformic acid, reducing agents
Sodium peroxide acetic acid, benzene, hydrogen sulfide metals, oxidizers, peroxyformic acid, phosphorous, reducers, sugars, water
Sulfides acids
Sulfuric acid potassium chlorates, potassium perchlorate, potassium permanganate