Explore

@gettyimages

You have just learned about the importance of WHMIS in school and in the workplace. WHMIS uses a classification system to indicate specific hazards and properties of products. There are six main classes and some sub classes. In this activity, you will learn about the main WHMIS symbols.

WHMIS groups products with similar properties or hazards into classes. The Controlled Products Regulations specifies the criteria used to place materials within each classification. WHMIS classifications are made by the manufacturer or supplier for products to be used in Canada.

There are six main WHMIS hazard classes. In general, each class has a specific symbol to help people quickly recognize the hazard. However, one hazard class has three symbols, so there are a total of eight symbols.

Class A - Compressed Gas

@gettyimages

A compressed gas is a material that is a gas at normal room temperature and pressure. The gas is placed under pressure or chilled to contain it, usually in a cylinder. These cylinders might explode if exposed to heat or if dropped.

Class B - Flammable and Combustible Material

@gettyimages

These materials can catch fire easily, at or just above normal room temperatures, and continue to burn. Some examples of flammable and combustible materials are butane, propane, gasoline, kerosene, aerosols, and even some special types of metals.

Class C - Oxidizing Material

@gettyimages

This symbol is placed on products that increase the risk of fire if they are in contact with flammable or combustible materials. Some materials that have this label include hydrogen peroxide (used in the pulp and paper industry), compressed oxygen (used in hospitals), and some acids.

Class D - Poisonous and Infectious Material

@gettyimages

These materials can cause harmful health effects. There are three divisions to this class.

Products with this label can kill or cause serious illness very quickly, even in small amounts. Examples of this type or product are sodium cyanide (used in extracting precious metals from ore) and hydrogen sulphide (used in manufacturing chemicals, dyes, rubber, rayon, etc.).

Products with this label can cause serious long-term health problems such as cancer as well as more immediate problems such as irritation of the eyes and skin. Products that have this label include asbestos (used in some insulation) and xylene (used in cleaners and paint thinners).

Products with this label contain micro-organisms that can cause illnesses such as hepatitis or salmonella (food poisoning).

Class E - Corrosive Material

@gettyimages

This label is found on chemicals that can burn through skin or other materials. Some examples are hydrochloric acid (used in processing steel, making batteries, and in many other processes), and nitric acid (found in fertilizers).

Class F - Dangerous Reactive Material

@gettyimages

Products with this label may explode or emit toxic gas. Cyanide (used in manufacturing paper, textiles, and plastics) is a product that has this label.

Click on the Play button to watch a video to learn more about WHMIS labels.