Proper Segregation of Chemical Classes

Partial List of Incompatible chemicals
(Toxic Hazards)

Substances in the left hand column should be stored and handled so that they cannot possibly accidentally contact corresponding substances in the center column, because toxic materials (right hand column) would be produced.

Arsenical Materials Any Reducing Agent Arsine
Azides Acids Hydrogen Azide
Cyanides Acids Hydrogen Cyanide
Hypochlorites Acids Chlorine or
Hypochlorous Acid
Nitrates Sulfuric Acid Nitrogen Dioxide
Nitric acid Copper, Brass,
Heavy Metals
Nitrogen Dioxide
Nitrites Acids Nitrous Fumes
Phosphorus Caustic Alkalies/
Selenides Reducers Hydrogen Selenide
Sulfides Acids Hydrogen Sulfide
Tellurides Reducers Hydrogen Telluride

Reactive Chemicals

Reactive chemicals are substances which, under certain ambient or induced conditions, enter into violent reactions with spontaneous generation of large quantities of heat, light, gases (flammable and non-flammable), or toxicants that can be destructive to lives and property. Types of reactive chemicals have been loosely categorized:


In general, protect explosive substances from shock, elevated temperatures, rapid temperature changes, and other reactive chemicals, Some examples: nitroglycerin, nitrocellulose, and organic peroxides. Many substances, when mixed, are potentially explosive (such as hydrazines and nitric acid).

Oxidizing and Reducing Substances

In many oxidizing and reducing reactions, both agents must be present. In some cases, one or the other substance may create a hazard by coming into contact with a normally innocuous substance. These reactions tend to generate heat and are often explosive, e.g., glycerol and potassium permanganate blended at room temperature for a few minutes react violently producing fire. The following examples of typical oxidizers may:

Increase Rate of Combustion
Aluminum nitrate Perchloric acid 60% or less
Ammonium persulfate Potassium chlorate
Barium chlorate Potassium dichromate
Barium peroxide Potassium nitrate
Calcium chlorate Potassium persulfate
Calcium nitrate Silver nitrate
Calcium peroxide Silver nitrite
Cupric nitrate Sodium perborate
Hydrogen peroxide Sodium perchlorate
Lead nitrate Sodium persulfate
Lithium hypochlorite Strontium chlorate
Lithium peroxide Strontium nitrate
Magnesium nitrate Strontium nitrite
Magnesium perchlorate Thorium nitrite
Magnesium peroxide Uranium nitrate
Nickel nitrate Zinc chlorate
Nitric acid 70% or less Zinc peroxide
Cause Spontaneous Ignition
Calcium hypochlorite Sodium chlorite (>40%)
Chromic acid Sodium peroxide
Hydrogen peroxide (27.5-52%) Sodium permanganate
Nitric acid Trichloroisocyanuric acid
Potassium bromate Sodium dichloroisocyanurate
Potassium permanganate
Decompose with Catalyst or Heat
Ammonium dichromate Perchloric acid (60-72.5%)
Hydrogen peroxide (52-91%) Potassium dichloroisocyanurate
Calcium hypochlorite (>50%) Sodium dichloroisocyanurate
Cause Explosive Reaction when exposed to Catalyst, Heat, Shock, or Friction
Ammonium perchlorate Perchloric acid
Ammonium permanganate Potassium superoxide

Water Sensitive Substances

These chemicals react with water, steam, and moisture in the air to evolve heat and/or flammable or explosive gases. Isolate water-sensitive substances from other reactive compounds, and store in a cool, waterproof area. Some substances that liberate only hear are: strong acids and bases, acid anhydrides and sulfides. Some substances that liberate flammable gases when exposed to water are: alkali metals, hydrides, nitrites, carbides, and anhydrous metallic salts.

Air Reactive Substances

These materials are capable of rapid release of energy by themselves, as by self-reaction or polymerization, for example white phosphorous. Also included in this category are substances that can be easily ignited by common sources of heat when mixed with air, for example: alkali metals, ammonium nitrate, ammonium perchlorate, ammonium permanganate, benzoyl peroxide, boron hydrides, dinitrobenzene, lithium hydride, sulfur.

Acid Reactive Substances

These chemicals react with acid to evolve heat, flammable and/or explosive gases, and toxicants. Some examples are: alkali metals, hydroxides, carbides, nitrites, arsenic and related elements, cyanides, sulfides, and structural alloys (most metals).

Special Organic Compounds

These compounds are unstable and may decompose spontaneously or through contact with the immediate environment (air, water, and other reactants). Some examples: diazonium compounds, diazomethane, chlorination intermediates, butadiene, nitration intermediates, organic sulfates, polymerization reactions, and highly nitrated compounds.

Pyrophoric Agents

Pyrophoric agents burn when exposed to air. In general, they require absolute protection against air. Examples: phosphorus and activated zinc.

Incompatible Chemicals

The following is a partial listing of incompatible chemicals. A more complete listing may be found in NFPA and various laboratory and chemical reference manuals.

ACETIC ACID Chromic acid, nitric acid, hydroxyl-containing compounds, ethylene glycol, perchloric acid, peroxides, and permanganates
ACETONE Concentrated sulfuric and nitric acid mixtures or chloroform and bases
ACETYLENE Copper tubing, halides, silver, mercury and their compounds
ALKALI METALS Aluminum, calcium, lithium, magnesium, potassium and sodium with water or chlorinated hydrocarbon, carbon dioxide, halogens
AMMONIA, ANHYDROUS Mercury, halogens, calcium hypochlorite, hydrogen fluoride
ANILINE Nitric acid and hydrogen peroxide
BROMINE Ammonia, acetylene, butadiene, butane, hydrogen, sodium carbide, turpentine
CHLORATES Ammonium salts, acids, metal powders, sulfur, finely divided organic and combustible materials
CHROMIC ACID Acetic acid, alcohol, camphor, flammable liquids, glycerol, naphthalene
CHLORINE Ammonia, acetylene, butadiene, benzene and other petroleum fractions, hydrogen, sodium carbides, powdered metals
COPPER SALTS Acetylene, hydrogen peroxide
ETHYLENEDIAMINE Greater than 3 percent with methylene chloride (explosive)
FLAMMABLE LIQUIDS Ammonium nitrate, chromic acid, hydrogen peroxide, halogens, nitric acid, sodium peroxide
HYDROCARBONS (Butane, Halogens, chromic acid, peroxides Propane, Benzene)
HYDROGEN PEROXIDE Copper, chromium, iron, most metals and their salts, flammable fluids, aniline, and nitromethane
HYDROGEN SULFIDE Nitric acid and oxidizing gases
IODINE Acetylene, ammonia
MERCURY Acetylene, hydrogen
METHYLENE CHLORIDE Greater than 3 percent ethylenediamine (explosive)
NITRIC ACID Acetic, chromic and hydrochloric acids, aniline, carbon, hydrogen sulfide, flammable fluids, or gases which are readily nitrated
OXYGEN Oils, grease, hydrogen, flammable liquids, solids, and gases
OXALIC ACID Mercury, silver
PERCHLORIC ACID Acetic anhydride, alcohol, organic materials, e.g., wood, paper, grease, and oils
PHOSPHORUS Air, alkalis, oxygen, reducing agents
SODIUM Carbon dioxide, carbon tetrachloride, water
SODIUM PEROXIDE Any oxidizable substances; acetic acid, acetic anhydride, benzaldehyde, carbon disulfide, glycerol, ethylene glycol, ethyl acetate, methanol
SULFURIC ACID Potassium chlorate, potassium perchlorate, potassium permanganate


Reviewed May, 18, 2011