WHMIS: Physical hazard classes

All 17 questions in this test

Every question and its answer choices. The correct answers and explanations appear when you take the test above.

1. Why are simple asphyxiants especially dangerous in confined spaces?

   1. They only work in large open areas
   2. They are bright red and block vision
   3. They are colourless and odourless and give no warning
   4. They smell strongly and make workers panic in tight areas

2. A product is described as pyrophoric. What does that mean?

   1. It only burns when heated above 100 °C
   2. It must be kept in direct sunlight
   3. It gives off a strong smell as soon as it is opened
   4. It can catch fire very quickly on contact with air

3. Which statement about oxidizers is true?

   1. They burn on their own even without fuel
   2. They do not burn but make fires hotter and faster
   3. They are only dangerous when frozen
   4. They make fires smaller by using up the oxygen around them

4. Why can a cylinder of compressed gas be dangerous even if the gas is not flammable?

   1. Compressed gases always cause cancer
   2. The high pressure can make it explode if heated
   3. The cylinder paint is toxic
   4. Compressed gases react with sunlight to form acid

5. Which three things must come together for a fire to start?

   1. Fuel, oxygen and heat
   2. Oxygen, light and cold
   3. Fuel, water and pressure
   4. Heat, dust and metal

6. How can a simple asphyxiant harm a worker?

   1. By making metal containers corrode
   2. By causing cancer after many years
   3. By burning the skin on contact
   4. By pushing oxygen out of the air

7. Vapour from a flammable liquid drifts along the floor and is lit by a distant pilot light. The flame then travels back to the container. What is this called?

   1. Boil-over
   2. Sublimation
   3. Backdraft
   4. Flashback

8. A label says the product releases flammable gas in contact with water. What is the risk?

   1. Water makes the product completely safe
   2. Water causes the product to lose its smell
   3. Water can release a gas that may ignite
   4. Water turns the product into a solid

9. How do self-heating substances differ from pyrophoric products?

   1. They never catch fire under any condition
   2. They ignite only after a longer time or in large amounts
   3. They only react when mixed with water
   4. They ignite instantly on contact with air, even in tiny amounts

10. What is the special hazard of a refrigerated liquefied gas?

    1. It is very cold and can cause cryogenic burns
    2. It turns into a solid that blocks drains
    3. It glows and can damage eyesight
    4. It is very hot and can cause steam burns

11. What is the main hazard of products in the flammable liquids class?

    1. Fire or explosion
    2. Skin allergy
    3. Radiation burns
    4. Hearing loss

12. What does the "corrosive to metals" class warn about?

    1. The product makes metal tools magnetic
    2. The product rusts only plastic containers
    3. The product can chemically damage or destroy metal
    4. The product is safe for skin but not metal

13. What is the class "physical hazards not otherwise classified" for?

    1. Health effects that appear years after the first exposure
    2. Reaction hazards not covered by any other physical class
    3. Products too small to need a label
    4. Products whose supplier is unknown

14. Which product fits the WHMIS class "chemicals under pressure"?

    1. A gas cylinder filled with compressed oxygen for welding
    2. A liquid pressurized with gas in a non-aerosol container
    3. A liquid in an open bucket
    4. A spray can of air freshener

15. Why are combustible dusts a hazard?

    1. Dust always contains infectious organisms
    2. Dust blocks radio signals at work
    3. Dust reacts with water to form acid
    4. Fine particles in the air can ignite or explode

16. How does an oxidizer create a fire hazard?

    1. It absorbs heat and puts fires out
    2. It makes a fire produce less smoke
    3. It only burns when mixed with water
    4. It can cause or intensify a fire

17. What is the key hazard of organic peroxides?

    1. They cause hearing loss over time
    2. They may cause a fire or explosion if heated
    3. They freeze skin on contact
    4. They are harmful only to fish and other aquatic life