1.8: Warning Symbols (WHMIS 1988)
Listed below are symbols used to identify hazardous materials, which all workers should be familiar with. The symbols in circles indicate hazard classes and divisions set by WHMIS. These are generally found on products that are usually sold in large quantities to manufacturers and contractors, and they must carry the correct labels. The hazard symbols in triangles are set by Consumer and Corporate Affairs. These are used on products that are usually sold to individual consumers in small quantities.
Class A – Compressed Gas
This class includes compressed gases, dissolved gases, and gases liquefied by compression or refrigeration (Figure 4).
Examples: Gas cylinders for barbeques, small blow torches, and butane lighters all contain compressed gas.
Although not a part of the WHMIS 1988 program, this symbol (Figure 5) is a part of the new WHMIS 2015 program and the GHS. The explosion symbol is often found on small consumer containers of products stored under pressure. Bottles of compressed gas, propane, and other gases must be handled with extreme care. Protective caps should be kept on the tanks when they are not in use. Whether the tank is full or empty, it still contains tremendous pressure.
Class B – Flammable and Combustible Material
In this class are solids, liquids, and gases capable of catching fire or exploding in the presence of a source of ignition (Figure 6).
There are six divisions within Class B:
- Division 1: flammable gases
- Division 2: flammable liquids
- Division 3: combustible liquids
- Division 4: flammable solids
- Division 5: flammable aerosols
- Division 6: reactive flammable materials
Examples: White phosphorus, acetone, and butane. Flammable liquids such as sterno is more easily ignited than combustible liquids such as lamp oil for fondues.
When concentrations of flammable liquids are present, there is a great risk of these fumes being ignited by an open flame or spark. Fire extinguishers should also be on hand and in operating order. Take the necessary precautions to ensure using these flammable liquids safely.
Class C – Oxidizing Material
In this class are unstable substances that combine with oxygen and increase the risk of fire if they come in contact with flammable or combustible materials (Figure 7).
Examples: Cleaning chemicals.
Class D – Poisonous and Infectious Materials
There are three divisions in Class D: Division 1, Division 2, and Division 3.
Division 1
This division covers materials that cause immediate and serious toxic effects (Figure 8). They can cause the death of a person exposed to small amounts.
Examples: Cleaning chemicals.
Division 2
In this division are materials that cause other toxic effects (Figure 9). Some cause immediate skin or eye irritation. Others can cause long-term effects in a person who is repeatedly exposed to small amounts.
Examples: Pesticides and rodenticides.
Division 3
Biohazardous infectious materials are in this division (Figure 10). It applies to materials that contain harmful micro-organisms.
Examples: Some foods that can support bacterial growth such as salmonella bacteria or E. coli.
Class E – Corrosive Material
This division covers caustic or acid materials, which can destroy the skin or eat through metals (Figure 11).
Examples: cleaning agents and degreasing agents.
Chemical burn
Chemicals that cause burns are identified by the symbol shown in Figure 12 and are also part of Class E, corrosive material.
Class F: Dangerously Reactive Material
These products may self-react dangerously (for example, they may explode) upon standing or when exposed to physical shock or to increased pressure or temperature, or they emit toxic gases when exposed to water (Figure 13).