2025 WHMIS Solutions: Training, Implementation & Compliance by Expert Chemists

Everything You Need to Know About WHMIS in Canada

 

WHMIS (Workplace Hazardous Materials Information System) is Canada's national standard for chemical hazard communication. Since its harmonization with the GHS (Globally Harmonized System), it standardizes worker protection through three inseparable tools: Labels, Safety Data Sheets (SDS), and Training.

 

WHMIS 2015 and the December 2022 Update

 

Regulations have evolved. Today, we apply the WHMIS 2015 criteria, which was enhanced in 2022 to integrate the GHS 7th and 8th editions. These changes particularly affect the classification of flammable gases, aerosols, and chemicals under pressure.

The 3-year transition period to update classifications and SDS ended in December 2025. Is your inventory still compliant? Avoid penalties by regularizing your situation now.

 

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WHMIS Hazard Classes: Understanding the Risks

 

1. Physical Hazards

 

These hazards involve material or mechanical damage (fires, explosions, metal corrosion) that can also cause serious physical injury

Exploding Bomb

This pictogram warns of a risk of violent chemical reaction generating high-temperature gases and pressure.

• Target Classes: Self-reactive substances and Organic peroxides (Types A and B).
• Expert Tip: It is imperative to protect these products from heat, shock, and static electricity. Store them in minimal quantities, ideally in an explosion-proof refrigerator.

 

Gas Cylinder

With the exception of aerosols, this symbol indicates contents under high pressure.

• Target Classes: Compressed, liquefied, or dissolved gases, and chemicals under pressure.
• Expert Tip: A broken cylinder can turn into a deadly projectile. Always secure cylinders upright and keep them away from heat sources to prevent container explosion.

 

Flame

The flame pictogram covers the widest range of hazard classes in WHMIS. In general, it indicates a fire risk.

This pictogram covers the largest number of hazard classes (11 in total).

• Target Classes: Flammable gases, liquids, and solids; aerosols and chemicals under pressure; pyrophoric materials (spontaneously ignite in air); self-heating substances; self-reactive substances; and organic peroxides.
• Expert Tip: Storage is complex here. For example, self-heating materials should not be stored with flammable liquids. Rely on TDG (Transport of Dangerous Goods) classifications to organize your storage area.

 

Flame Over Circle

These products do not burn themselves, but they provide the oxygen necessary to violently intensify a fire.

• Target Classes: Oxidizing gases, liquids, and solids.
• Note: Never store oxidizers on wooden pallets or in cardboard; some can ignite these materials through simple contact.

 

 

Corrosion

 Identifies products that chemically attack metals.

• Target Classes: Corrosive to metals.
• Vigilance: Use only corrosion-resistant containers. Note that this pictogram groups both acids and bases: their accidental mixing can cause a violent exothermic reaction.

 

2. Health Hazards

 

Health hazards are those that affect human health. Their effects can be immediate or long-term, localized or systemic, and sometimes lethal. WHMIS groups health hazards under 5 pictograms, in addition to hazards not identified by a symbol.

 

Corrosion

As mentioned above, this is the only WHMIS pictogram used for both physical and health hazards. In this section, we focus on health risks. For health hazards, this symbol informs workers that the product can cause corrosion to the skin, eyes, or respiratory tract. Corrosion is characterized by irreversible damage such as necrosis, burns, ulcers, bleeding, and blisters.

 

• Target Classes: Skin corrosion and serious eye damage.
• Did You Know? Acids and alkaline products (bases) act differently on your skin. An acid causes an immediate pain signal. However, a base triggers a saponification reaction; the base literally turns your skin into soap! This reaction is often not painful at first, even though the damage has already begun.
• Safety: When this pictogram is present, emergency body and eye showers must be near the workstation. ANSI Z358.1-2014 standards must be followed during installation. The use of PPE such as gloves and safety goggles is mandatory.

 

Skull and Crossbones

This pictogram warns workers of acute toxicity. Acute toxicity refers to adverse effects occurring following the administration of a single dose (or multiple doses within 24 hours) that can lead to death. WHMIS considers ingestion, inhalation, and skin contact. For inhalation, three types of exposure are possible: gas, vapor, or dusts and mists. Note that a product toxic via the skin can kill without leaving a trace or burn. Some products may also release toxic gas upon contact with water.

 

• Target Classes: Acute toxicity (oral, dermal, and inhalation).
• Indicators: Based on and . The smaller these doses, the more lethal the product.
• Safety: Just as with corrosive products, emergency showers must be accessible. Every measure must be taken to minimize exposure.

 

Health Hazard

This pictogram concerns long-term damage, often invisible in the immediate term. Since it is used for several classes, it is vital to read the label and SDS to know the specific risk.

 

• Target Classes: Carcinogenicity, mutagenicity, reproductive toxicity, respiratory sensitization, specific target organ toxicity (single and repeated exposure), and aspiration hazard.
• Expert Tip: Damage may only appear years later. Rigorous use of PPE is your only barrier against these latent risks.

 

Exclamation Mark

This pictogram indicates a product that impairs health. You will not protect yourself the same way from a harmful product as you would from an irritant or sensitizer.

• Target Classes: Acute toxicity – Category 4 (oral, dermal, inhalation), skin and eye irritation, skin sensitization, and specific target organ toxicity – Category 3 (narcotic effects and respiratory tract irritation).
• Note: It also covers narcotic effects (dizziness). Do not ignore this symbol: skin sensitization can become a permanent allergy.

 

Biohazardous Infectious Materials

The "Biohazardous Infectious Materials" pictogram is unique to Canada. This is why it is circular and not a red-bordered diamond. Read the labels carefully, as hazard statements vary depending on the infectious agent.

 

 

3. Hazards Without a Pictogram and PHNOC/HHNOC

The absence of a symbol does not mean an absence of danger.

 

• Hazards Without a Pictogram: Includes combustible dusts, simple asphyxiants, flammable liquids – Category 4, eye irritation – Category 2B, and reproductive toxicity – effects on or via lactation.
• Physical Hazards Not Otherwise Classified (PHNOC) / Health Hazards Not Otherwise Classified (HHNOC): This class allows for the inclusion of a specific danger not otherwise present in the regulations. While no specific symbol is prescribed, it is permitted in Canada to use one of the existing WHMIS pictograms if appropriate.

 

Example: For respiratory tract corrosion, a product can be classified as HHNOC – Corrosion – Category 1 and display the corrosion pictogram.

 

👉 Read our full guide: What is WHMIS?