WHMIS Hazard Classes and Pictograms 2 — Questions and Answers
Question 1: Which WHMIS 2015 pictogram depicts a cylinder shape and indicates gases stored under pressure?
- Exploding bomb
- Corrosion
- Gas cylinder (Correct answer)
- Flame
Correct answer: Gas cylinder
The gas cylinder pictogram applies to compressed, liquefied, dissolved, and refrigerated liquefied gases stored under pressure.
Question 2: The 'flame over circle' pictogram in WHMIS specifically identifies which type of hazard?
- Flammable aerosols
- Oxidizing substances that can intensify fires (Correct answer)
- Self-heating materials
- Pyrophoric liquids
Correct answer: Oxidizing substances that can intensify fires
The flame over circle pictogram indicates oxidizing substances, which can provide oxygen to support and intensify combustion.
Question 3: Sodium metal, which reacts violently with water to release hydrogen gas, belongs to which WHMIS hazard class?
- Flammable solids (Class 4.1)
- Oxidizing solids (Class 5.1)
- Substances that emit flammable gases on contact with water (Class 4.3) (Correct answer)
- Pyrophoric solids (Class 4.2)
Correct answer: Substances that emit flammable gases on contact with water (Class 4.3)
Class 4.3 covers substances that react with water to produce flammable gases, such as sodium or potassium metals.
Question 4: A Dewar flask of liquid nitrogen in a laboratory would most prominently display which WHMIS pictogram?
- Skull and crossbones
- Gas cylinder (Correct answer)
- Exclamation mark
- Health hazard
Correct answer: Gas cylinder
Liquid nitrogen is a refrigerated liquefied gas under pressure, so it carries the gas cylinder pictogram.
Question 5: Industrial-strength hydrogen peroxide at concentrations above 60% is most likely classified under which WHMIS hazard category?
- Flammable liquids
- Corrosive to metals
- Oxidizing liquids (Correct answer)
- Biohazardous infectious materials
Correct answer: Oxidizing liquids
High-concentration hydrogen peroxide is a powerful oxidizing liquid that can cause fires or explosions when it contacts organic material.
Question 6: Which WHMIS pictogram would appear on a product that can detonate or explode when subjected to heat or shock?
- Flame
- Gas cylinder
- Exploding bomb (Correct answer)
- Corrosion
Correct answer: Exploding bomb
The exploding bomb pictogram is used for explosives, self-reactive substances (certain types), and organic peroxides that pose explosion risks.
Question 7: A substance that ignites spontaneously when exposed to air at ambient temperatures is classified under which WHMIS class?
- Class 3 – Flammable Liquids
- Class 4.2 – Pyrophoric Materials (Correct answer)
- Class 4.1 – Flammable Solids
- Class 5.1 – Oxidizing Substances
Correct answer: Class 4.2 – Pyrophoric Materials
Pyrophoric materials (Class 4.2) are defined by their ability to self-ignite within five minutes of air exposure.
WHMIS Hazard Classes and Pictograms 2
Which WHMIS 2015 pictogram depicts a cylinder shape and indicates gases stored under pressure?