Advanced Photon Source

A U.S. Department of Energy, Office of Science,
Office of Basic Energy Sciences national synchrotron x-ray research facility

Proper Segregation of Chemical Classes

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.

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:

Explosives

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:

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.