WHMIS Study Guide 2026

What WHMIS is and who does what

WHMIS stands for the Workplace Hazardous Materials Information System. It is Canada's national hazard communication standard. Its job is to make sure that people who work with hazardous products know the dangers and how to protect themselves.

WHMIS gives you information in three main ways:

• Labels on the containers of hazardous products.
• Safety data sheets (SDSs) with detailed information about each product.
• Worker education and training about the hazards and safe work procedures in your workplace.

WHMIS 2015 follows the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). The GHS is an international approach, so pictograms and safety data sheets look much the same in many countries.

Federal and provincial laws work together

At the federal level, the Hazardous Products Act and the Hazardous Products Regulations set the rules for suppliers: how to classify products and what must be on labels and SDSs. Health Canada administers these laws.

The rules for employers come from occupational health and safety (OHS) law. There are 13 federal, provincial and territorial OHS agencies, and each one sets WHMIS requirements for employers in its area. Workplaces under federal jurisdiction are covered by the Labour Program of Employment and Social Development Canada.

Duties of suppliers, employers and workers

Recent changes

The Hazardous Products Regulations were amended. The changes came into force on December 15, 2022, and the 3-year transition period ended on December 14, 2025. The changes added a new physical hazard class, chemicals under pressure, renamed "flammable aerosols" to aerosols (with a new Category 3 for non-flammable aerosols), and moved pyrophoric gases into flammable gases, Category 1A.

Hazard groups, classes and categories

WHMIS sorts hazards into two groups. Each group is divided into hazard classes, and most classes are split into categories.

• Physical hazards are based on physical or chemical properties, such as catching fire, reacting dangerously or corroding metal.
• Health hazards are based on the ability to harm the body, such as eye irritation or cancer.

The GHS also has an environmental hazard group, but WHMIS did not adopt it.

Categories and types

Category 1 is the most severe level in its class. Category 2 is more hazardous than Category 3, with a few exceptions. Some categories are called types and use letters. For example, organic peroxides and self-reactive substances run from Type A to Type G.

Gases under pressure are different. Their categories (compressed, liquefied, refrigerated liquefied and dissolved gas) describe the physical state of the gas, not how dangerous it is.

A simple asphyxiant is a gas that can push oxygen out of the air and cause rapid suffocation, especially in small or closed spaces. Combustible dusts are fine particles that can form an explosive mixture with air.

The WHMIS pictograms

A pictogram is a small picture that shows the type of hazard at a glance. Most WHMIS pictograms have a black symbol on a white background with a red border shaped like a square set on one of its points (a diamond).

The pictogram for biohazardous infectious materials is different. It has a black circle border instead of a red diamond. It warns of organisms or their toxins that can cause disease in people or animals.

Which hazards each pictogram covers

Products with two pictograms

• Self-reactive substances and organic peroxides of Type B show both the flame and the exploding bomb.
• Chemicals under pressure, Categories 1 and 2, show both the flame and the gas cylinder.

Hazards with no pictogram

Some hazardous products need a label but no pictogram. Examples are aerosols Category 3, flammable gases Category 2, flammable liquids Category 4, combustible dusts, simple asphyxiants and eye irritation Category 2B. The label and SDS must still show the signal word, hazard statements and the other required elements.

Supplier labels

The supplier label is the label a hazardous product has when it arrives at your workplace. Suppliers must attach it to the product or its container. Sending a label with the shipping papers is not enough.

What a supplier label must show

• Product identifier: the name of the product, matching the SDS.
• Initial supplier identifier: the name, address and phone number of the Canadian manufacturer or importer.
• Pictograms for the hazards.
• Signal word: "Danger" or "Warning".
• Hazard statements: standard phrases that describe the hazard.
• Precautionary statements: how to prevent harm and what to do if exposed.
• Supplemental information, when the product's classification requires it.

The pictogram, signal word and hazard statement must be grouped together on the label. The label must be easy to read and must stand out from other information on the container.

Signal words and statements

WHMIS uses only two signal words. "Danger" is for more severe hazards and "Warning" for less severe ones. If a product qualifies for both, only "Danger" is shown. Some categories have no signal word.

Hazard statements show how serious a hazard is. For example, "May cause cancer" is more serious than "Suspected of causing cancer".

Precautionary statements come in five types: general, prevention, response (including first aid), storage and disposal.

Other label rules

• Supplier labels must be in English and French, on one bilingual label or two separate labels.
• The hatched (slashed) border from WHMIS 1988 is no longer required, but some labels still have it.
• Containers of 100 mL or less may leave off the hazard and precautionary statements only.
• Hazardous ingredients do not have to be listed on the label, but they must be on the SDS.
• Suppliers must update labels within 180 days of learning significant new data.

Workplace labels

A workplace label is a label the employer makes for use inside the workplace. The detailed rules come from your province or territory, or from the Canada Labour Code for federal workplaces.

When a workplace label is needed

• A hazardous product is made in the workplace and used there.
• A product is decanted (poured or transferred) into another container.
• The supplier label is lost or cannot be read.

A full workplace label is not needed if a decanted product is used right away, or stays under the control of the person who poured it (for example, one person during one shift). Even then, the container must show the product identifier.

What a workplace label shows

• The product identifier, matching the name on the SDS.
• Safe handling information, which may include pictograms or other supplier label information.
• A reference to the SDS, if one is available.

If you cannot read a label

Always check for a label before you use a product. Do not use a product that is unlabelled or has a label you cannot read. Tell your supervisor, who must arrange a workplace label. If you are not sure how to use or store a product, ask before you start.

Safety data sheets (SDSs)

A safety data sheet gives detailed information about a hazardous product. The supplier usually prepares it. An employer that makes a hazardous product for its own use must prepare one too.

Every SDS has 16 sections in the same order:

Sections 12 to 15 must have their headings, but the supplier may choose not to fill them in.

SDS rules to remember

• An SDS must be in English and French. Email or USB is fine, but a website link alone is not.
• Suppliers must update an SDS within 90 days of learning significant new data.
• The federal rules no longer make suppliers update every SDS every 3 years. Some provinces and territories still make employers look for an updated SDS every 3 years.
• Employers must make SDSs readily available to exposed workers and to the health and safety committee or representative.
• If SDSs are on a computer, workers must be trained to use it, the devices must work, and a paper copy must be available on request.

Education and training

WHMIS separates education from training:

• Education is general information you can take from job to job, such as how WHMIS works and what labels and SDSs show.
• Training is specific to your site and job: how to store, handle, use and dispose of the products where you work, and what to do in an emergency or spill.

Who must be trained

• Workers who may be exposed to a hazardous product, including during maintenance or emergencies.
• Workers who use, store, handle or dispose of hazardous products.
• People who supervise or manage those workers.
• People involved in emergency response.

What training covers

• What supplier and workplace labels mean.
• What information is on an SDS and how to find it.
• Procedures for safe use, handling and disposal.
• Procedures for products in pipes, piping systems, vessels or tank cars.
• Procedures when a product may be in the air and workers may breathe it.
• All emergency procedures for the products.

Reviews, refreshers and tests

Employers must develop, implement and maintain a WHMIS education and training program. CCOHS advises reviewing it at least once a year, and sooner when work conditions, processes or hazard information change. Employers are expected to consult the health and safety committee or representative.

Refresher training is needed when conditions change, when new products arrive, or when new hazard or safe-use information becomes available. Some provinces and territories also expect employers to check workers' knowledge, for example with a written test or a practical demonstration.

An employer may use an outside trainer, but the employer is still legally responsible for protecting workers. If you change jobs, your general education may carry over, but your new workplace must train you on its own products and procedures.

Safe handling and storage basics

Always read the label and the SDS before you use a product. Section 7 of the SDS explains safe storage and lists materials the product must be kept away from. Section 8 tells you which PPE to wear.

CCOHS gives these tips for products with the flame pictogram:

• Keep them away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
• Check for hidden ignition sources, such as pilot lights, before use.
• Use them only in well-ventilated areas.
• Store them in approved equipment, such as flammable storage cabinets, and avoid storing them in basements.
• Keep containers tightly closed and check them often for leaks or damage.
• Use the smallest amount needed and avoid storing large amounts.
• Ground and bond containers when needed to prevent static sparks, and use non-sparking tools with volatile liquids.
• Do not pierce or burn aerosol cans, even when empty.
• Do not soak up spills with paper towels or sawdust, because they burn. Report leaks and spills to your supervisor right away.

Tips for your WHMIS quiz

• Learn all nine WHMIS pictograms and one hazard for each.
• Remember the two signal words and which one is more serious.
• Know when a workplace label is needed and what it shows.
• Know the 16 SDS section names, especially 1, 2, 4, 5, 6, 7, 8 and 16.
• Know the update times: SDS within 90 days, label within 180 days of significant new data.
• Remember the duties: suppliers classify and label, employers train and control hazards, workers take part and report.
• Read each question carefully. Words like "supplier", "workplace label" and "decanted" change the answer.

Your own employer's quiz may also ask about products and procedures at your site. Ask your supervisor which products you will use and read their labels and SDSs before your training.