Chemical Hazard Classes

Note that the class numbers are just a classification tool; they DO NOT indicate a relative degree of danger. You are not required to memorize these hazardous chemicals; we are going over them because you are likely to come in contact with hazardous chemicals at a surface mine. Let us now take a brief but closer look at each class.

Class 1 - Explosives

Explosives are chemicals designed to function by explosion, that is, an extremely rapid release of gas and heat. Surface mines frequently use explosives in blasting operations.

Class 2 - Gases

Gases can be hazardous when they are flammable, poisonous, or compressed. At surface mines, welding tools, air-purging systems, and liquid storage tanks can all contain hazardous gases.

Class 3 - Flammable and Combustible Liquids

Flammable and combustible liquids give off flammable vapors. The flash point is the minimum temperature at which vapors can form an ignitable mixture with surface air. Various types of fuel are considered Class 3 chemicals.

Class 4 - Flammable Solids

Flammable solids can ignite easily, even spontaneously, or are dangerous when wet. Even an oily rag can be considered a flammable solid requiring careful storage or disposal.

Class 5 - Oxidizers and Organic Peroxide

Oxidizers can release oxygen during chemical reactions. This extra oxygen can contribute to the combustion of other materials. This can make firefighting more difficult. Common oxidizers include bleach and ammonium nitrate fuel oil (ANFO).

Class 6 - Toxic Materials and Infectious Substances

Toxic chemicals are poisonous when consumed, touched, or breathed. Surface mines may have toxic chemicals in overburden. Infectious substances contain germs and may be present in lavatories.

Class 7 - Radioactive Material

Radioactive material continually emits potentially harmful radiation. Radioactive exposure is possible when encountering radon or mining uranium and other radioactive metals.

Class 8 - Corrosive Materials

Corrosive materials can chemically react with living tissue. This can cause severe pain, damage, and even death. Corrosive materials can also damage equipment. Corrosive materials include battery acid, rock salt, acid mine drainage (AMD), and many others.

Class 9 - Miscellaneous Hazardous Materials

Miscellaneous hazardous materials are dangerous materials that do not meet the requirements of other categories. Surface mines may contain miscellaneous hazardous materials such as asbestos and dry ice.

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