NEWEST CERTIFIED HAZARDOUS MATERIALS
SUPERVISOR (WSO-CHMS) CERTIFICATION
EXAM OFFERED BY THE WORLD SAFETY
ORGANIZATION | COMPLETE EXAM Q&A WITH
RATIONALES
1. Which of the following best describes a
compound?
A) A mixture of two or more substances that retain
their individual properties
B) A single element that cannot be broken down by
chemical means
C) Two or more elements chemically bonded in a
fixed ratio
D) A solution where one substance is dissolved in
another
Correct answer: C
Rationale: A compound consists of two or more
elements chemically combined in a fixed proportion,
giving it properties different from its constituent
elements.
2. In toxicology, the term "dose-response
relationship" refers to:
,A) The speed at which a chemical evaporates
B) The correlation between the amount of exposure
and the severity of effect
C) The route through which a chemical enters the
body
D) The time required for a chemical to degrade
Correct answer: B
Rationale: The dose-response relationship describes
how the magnitude of exposure (dose) influences the
biological response (effect).
3. Which hazard class under the DOT system includes
materials that are capable of causing burns on
contact with skin?
A) Class 2 – Gases
B) Class 5 – Oxidizers
C) Class 8 – Corrosives
D) Class 9 – Miscellaneous
Correct answer: C
Rationale: Class 8 hazards are corrosive materials
that can cause severe skin and eye damage.
,4. The primary purpose of a Safety Data Sheet (SDS)
is to:
A) Provide shipping instructions for hazardous
materials
B) Offer detailed information on the hazards,
handling, and emergency measures for a chemical
C) List the price and supplier of a chemical product
D) Serve as a legal contract between manufacturer
and buyer
Correct answer: B
Rationale: An SDS communicates essential safety,
handling, and emergency response information about
a chemical to workers and emergency responders.
5. Which instrument is most appropriate for detecting
volatile organic compounds (VOCs) in the field?
A) Thermometer
B) Photoionization detector (PID)
C) Geiger-Müller counter
D) Anemometer
Correct answer: B
, Rationale: A PID is a direct-reading instrument used
to detect volatile organic compounds (VOCs) in air
during field operations.
6. Under RCRA, a "Small Quantity Generator" (SQG)
generates how much hazardous waste per month?
A) Less than 100 kg
B) Between 100 kg and 1,000 kg
C) Between 1,000 kg and 10,000 kg
D) More than 10,000 kg
Correct answer: B
Rationale: An SQG generates between 100 kg and
1,000 kg of hazardous waste per month.
7. What does "LC50" measure in toxicology?
A) Lethal concentration that kills 50% of a test
population
B) The lowest concentration that causes any
observable effect
C) The concentration at which a chemical becomes
non-toxic
D) The safe exposure limit for workers
Correct answer: A
SUPERVISOR (WSO-CHMS) CERTIFICATION
EXAM OFFERED BY THE WORLD SAFETY
ORGANIZATION | COMPLETE EXAM Q&A WITH
RATIONALES
1. Which of the following best describes a
compound?
A) A mixture of two or more substances that retain
their individual properties
B) A single element that cannot be broken down by
chemical means
C) Two or more elements chemically bonded in a
fixed ratio
D) A solution where one substance is dissolved in
another
Correct answer: C
Rationale: A compound consists of two or more
elements chemically combined in a fixed proportion,
giving it properties different from its constituent
elements.
2. In toxicology, the term "dose-response
relationship" refers to:
,A) The speed at which a chemical evaporates
B) The correlation between the amount of exposure
and the severity of effect
C) The route through which a chemical enters the
body
D) The time required for a chemical to degrade
Correct answer: B
Rationale: The dose-response relationship describes
how the magnitude of exposure (dose) influences the
biological response (effect).
3. Which hazard class under the DOT system includes
materials that are capable of causing burns on
contact with skin?
A) Class 2 – Gases
B) Class 5 – Oxidizers
C) Class 8 – Corrosives
D) Class 9 – Miscellaneous
Correct answer: C
Rationale: Class 8 hazards are corrosive materials
that can cause severe skin and eye damage.
,4. The primary purpose of a Safety Data Sheet (SDS)
is to:
A) Provide shipping instructions for hazardous
materials
B) Offer detailed information on the hazards,
handling, and emergency measures for a chemical
C) List the price and supplier of a chemical product
D) Serve as a legal contract between manufacturer
and buyer
Correct answer: B
Rationale: An SDS communicates essential safety,
handling, and emergency response information about
a chemical to workers and emergency responders.
5. Which instrument is most appropriate for detecting
volatile organic compounds (VOCs) in the field?
A) Thermometer
B) Photoionization detector (PID)
C) Geiger-Müller counter
D) Anemometer
Correct answer: B
, Rationale: A PID is a direct-reading instrument used
to detect volatile organic compounds (VOCs) in air
during field operations.
6. Under RCRA, a "Small Quantity Generator" (SQG)
generates how much hazardous waste per month?
A) Less than 100 kg
B) Between 100 kg and 1,000 kg
C) Between 1,000 kg and 10,000 kg
D) More than 10,000 kg
Correct answer: B
Rationale: An SQG generates between 100 kg and
1,000 kg of hazardous waste per month.
7. What does "LC50" measure in toxicology?
A) Lethal concentration that kills 50% of a test
population
B) The lowest concentration that causes any
observable effect
C) The concentration at which a chemical becomes
non-toxic
D) The safe exposure limit for workers
Correct answer: A
