WHMIS Hazard Classes and Symbols 2 — Questions and Answers
Question 1: Which WHMIS 2015 pictogram shows a flame above a circle?
- Flammable liquids
- Oxidizing substances (Correct answer)
- Organic peroxides
- Explosive materials
Correct answer: Oxidizing substances
The flame over circle pictogram represents oxidizing substances, which can cause or intensify fire by releasing oxygen.
Question 2: Under WHMIS 2015, 'gases under pressure' includes which sub-categories?
- Compressed, liquefied, refrigerated liquefied, and dissolved gases (Correct answer)
- Only compressed and liquefied gases
- Flammable and non-flammable compressed gases only
- Dissolved and refrigerated gases only
Correct answer: Compressed, liquefied, refrigerated liquefied, and dissolved gases
WHMIS 2015 recognizes four types of gases under pressure: compressed, liquefied, refrigerated liquefied, and dissolved gases.
Question 3: The skull and crossbones pictogram in WHMIS 2015 indicates which hazard?
- Chronic health effects
- Acute toxicity (fatal or toxic) (Correct answer)
- Skin sensitization
- Biohazardous materials
Correct answer: Acute toxicity (fatal or toxic)
The skull and crossbones symbol signals acute toxicity — substances that are fatal or toxic in small amounts via ingestion, skin contact, or inhalation.
Question 4: Which class covers substances that can spontaneously ignite when exposed to air?
- Self-reactive substances
- Pyrophoric liquids and solids (Correct answer)
- Self-heating substances
- Flammable solids
Correct answer: Pyrophoric liquids and solids
Pyrophoric liquids and solids ignite spontaneously within 5 minutes of contact with air, unlike self-heating substances that require time.
Question 5: What does the exclamation mark pictogram in WHMIS 2015 represent?
- Explosive hazard
- Severe acute toxicity
- Moderate hazards like skin/eye irritation or specific target organ toxicity (single exposure) (Correct answer)
- Carcinogenicity
Correct answer: Moderate hazards like skin/eye irritation or specific target organ toxicity (single exposure)
The exclamation mark indicates less severe but still important hazards such as skin/eye irritation, skin sensitization, or STOT-single exposure category 3.
Question 6: Which WHMIS 2015 physical hazard class applies to dusts that can explode when suspended in air?
- Flammable solids
- Explosives
- Combustible dusts (Correct answer)
- Self-reactive substances
Correct answer: Combustible dusts
Combustible dusts is a WHMIS-specific hazard class for solid materials in fine particle form that can ignite and explode when suspended in air.
Question 7: Which pictogram is used specifically for biohazardous infectious materials in WHMIS 2015?
- Skull and crossbones
- The universal biohazard symbol (three interlocking circles) (Correct answer)
- Exclamation mark
- Health hazard (person with starburst on chest)
Correct answer: The universal biohazard symbol (three interlocking circles)
WHMIS 2015 uses the internationally recognized biohazard symbol — three interlocking arcs forming a trefoil — for biohazardous infectious materials.
WHMIS Hazard Classes and Symbols 2
Which WHMIS 2015 pictogram shows a flame above a circle?