How Many Hazmat Classes Are There?

HAZMAT road incidents have more than doubled over the past ten years. It's more important than ever to be careful with hazardous materials, and that all starts with being aware of DOT hazard classes.

How many HAZMAT classes are there anyway? What are they, and what should you know about them?

As someone going through training, these are things that you'll need to know. We're here to help. Read on to learn about the DOT hazard classes.

Class 1: Explosives

Explosives are substances or materials that are capable of producing an explosion. These are obviously quite dangerous under the right conditions even if they're safe when they're handled correctly. Improper handling or transportation of explosive materials can be deadly.

This class includes materials such as dynamite, fireworks, and ammunition, among others. Some of these things are routinely handled by average people or sold in stores, further increasing the risk.

Class 2: Gases

Gases are substances that are in a gaseous state (meaning they are neither liquids or solids) at normal atmospheric pressure and temperature. In other words, you can't see or touch them.

This class includes compressed gases (such as nitrogen and helium), liquefied gases (such as chlorine and hydrogen chloride), and gases that are dissolved under pressure (such as carbon dioxide).

There are also several classes of gases. They can be flammable, non-flammable, or toxic.

Class 3: Flammable Liquids

Flammable liquids are liquids that can easily ignite and burn under the right conditions. This class includes things such as gasoline, alcohol, and solvents. Many common cleaning agents and products also fit into the "flammable liquids" category.

Some people also refer to this class as combustible liquids or use the two terms interchangeably.

Class 4: Flammable Solids

Flammable solids are solid substances that can ignite and burn when they're exposed to heat, friction, or other sources of ignition. This class includes things such as matches, magnesium, and certain metal powders.

This category also has several subcategories.

The first subcategory is solids that are self-reactive, flammable, or desensitized explosives. The second category includes solids that may spontaneously combust under the right circumstances. the third category includes solids that will emit flammable gases if they're in contact with water.

These solids all fit into the same general category even though they pose different risks.

Class 5: Oxidizing Substances and Organic Peroxides

This class includes two subcategories: oxidizing substances and organic peroxides.

Oxidizing substances are materials that can cause or contribute to the combustion of other substances by providing oxygen. This class includes things such as hydrogen peroxide and certain chemicals used in bleaching agents.

Organic peroxides are substances and materials that contain the -O-O- structure. They are generally considered derivatives of hydrogen peroxide. They are often used as catalysts, initiators, and curing agents in various chemical processes.

They're super reactive compounds that can undergo spontaneous decomposition. That spontaneous decomposition can lead to serious consequences, such as combustion. It's important to know how to handle these materials safely.

Class 6: Toxic Substances and Infectious Substances

Like class 5, class 6 includes two separate categories: toxic substances and infectious substances.

Toxic substances include materials that can cause harm or death when ingested, inhaled, or absorbed through the skin. This class includes things such as pesticides, certain household chemicals, and poisonous gases, among others.

These are substances that someone may contact the poison control center for, for example. They require careful handling. Handlers may need to wear special gear to avoid skin contact or inhalation.

Infectious substances are materials that contain pathogens (like bacteria and viruses). They can cause illness in humans or animals. This class includes materials such as medical specimens, cultures, and biological products.

These also require careful handling and tend to come from medical facilities.

Class 7: Radioactive Materials

Radioactive materials are substances that emit radiation. These substances can cause serious harm to living creatures. Animals and humans alike can sustain serious damage from radiation, including cancer growth.

This class includes materials such as uranium, plutonium, and medical isotopes used in diagnostic and therapeutic procedures.

Class 8: Corrosive Substances

Corrosive substances are materials that can cause severe damage to living tissue or other materials upon contact. They can damage materials as soft as skin or as tough as stone or metal depending on the type of substance.

This class includes materials such as strong acids and strong bases (for example, acids such as sulfuric acid and hydrochloric acid, and bases, such as sodium hydroxide and potassium hydroxide), among others.

Corrosive substances are present in several cleaning agents. Many people think that all corrosive substances are liquids, but this isn't the case. They can be solids as well.

Class 9: Miscellaneous Dangerous Goods

This final class includes miscellaneous dangerous goods that do not fall into the other eight hazard classes but still pose risks during transportation.

This class includes materials such as asbestos, dry ice, and lithium batteries, among others.

Materials within this class may pose various hazards. They include environmental hazards, toxicity, or potential for combustion or explosion under the right conditions.

While these materials may not fit the specific criteria of the other hazard classes, they still require proper handling, packaging, and transport to help manage potential risks to human health, safety, and the environment.

In other words, if a material poses a risk of danger but it doesn't fit neatly into one of the other classes, it gets put into class nine so it still receives the care that it requires.

So How Many HAZMAT Classes Are There?

So how many HAZMAT classes are there? There are nine HAZMAT classes. Each class is distinct and has its own unique qualities and handling procedures.

Understanding each HAZMAT class will help you stay safe (and keep others safe). Remember, these are all hazardous materials. Regardless of their class, you need to use caution with them.

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