FDNY C-42 EXAM PREP PRACTICE QUESTIONS,
VERIFIED ANSWERS AND RATIONALES
(LATEST 2026 EDITION)
This comprehensive question practice exam package is
specifically engineered to guarantee a passing score on the
FDNY C-42 Certificate of Fitness examination. It features
verified multiple-choice questions covering critical fire
codes, material compatibility, personal protective equipment,
and emergency spill response protocols. Every question
includes a clear answer and a detailed, high-yield rationale,
making it the ultimate study tool to maximize your scores
and secure your certification.
Question 1
According to the NYC Fire Code, what is the maximum travel time
allowed for an employee to reach an emergency shower or
eyewash station from a hazardous corrosive handling area?
A) 30 seconds
B) 20 seconds
C) 10 seconds
D) 5 seconds
Answer: C
Rationale: The NYC Fire Code and ANSI Z358.1 standards
mandate that emergency eyewash and shower equipment
must be accessible within 10 seconds or less of walking
,travel time (approximately 55 feet) from the hazard, on an
unobstructed path on the same level.
Question 2
What formal chemical reaction hazard occurs when a strong acid
is directly and rapidly mixed with a concentrated base?
A) Endothermic sublimation
B) Exothermic neutralization
C) Catalytic ionization
D) Polymerization
Answer: B
Rationale: Mixing acids and bases results in a neutralization
reaction. This reaction is highly exothermic, meaning it
releases a significant amount of heat. If uncontrolled, it can
boil the liquid, melt plastic containers, and cause violent
splattering.
Question 3
Which of the following describes the core hazard of a Class 3
Oxidizer?
A) It causes skin burns on contact but does not support
combustion.
B) It causes a severe increase in the burning rate of combustible
materials with which it comes in contact.
C) It explodes spontaneously when exposed to regular ambient
air humidity.
D) It converts flammable liquids into inert gases.
,Answer: B
Rationale: Oxidizers readily yield oxygen or other oxidizing
gases, which severely intensifies and accelerates the
combustion rate of surrounding flammable or combustible
materials. Class 3 oxidizers cause a severe increase in the
burning rate.
Question 4
Under FDNY regulations, which document must be immediately
accessible to all employees handling hazardous chemicals in the
workplace?
A) The facility's corporate tax filing
B) The manufacturer's commercial retail catalog
C) Safety Data Sheets (SDS)
D) The local building occupancy certificate
Answer: C
Rationale: OSHA and FDNY regulations require Safety Data
Sheets (SDS) to be readily accessible to employees during all
work shifts. The SDS contains crucial details regarding
chemical properties, hazards, protective gear, and
emergency protocols.
Question 5
When storing containers of corrosive liquids, what structural
feature is required to prevent environmental contamination and
containment failure during a leak?
A) Absorbent wood shelving
B) Liquid-tight secondary containment
, C) Open floor drainage to public sewers
D) Elevated wire mesh racks without trays
Answer: B
Rationale: Secondary containment (such as trays, diking, or
containment pallets) is legally required for liquid hazardous
materials to collect leaks or spills from primary containers,
preventing them from spreading and causing reactions or
environmental damage.
Question 6
What is the primary operational reason why nitric acid must be
segregated from organic acids like acetic acid?
A) Nitric acid will freeze acetic acid solid.
B) Nitric acid acts as a powerful oxidizer that can react violently
and ignite organic compounds.
C) Acetic acid completely neutralizes the hazardous nature of
nitric acid.
D) They will vaporize into a non-toxic household cleaning solution.
Answer: B
Rationale: Nitric acid is not just a corrosive acid; it is also a
powerful oxidizer. Storing it next to organic acids or organic
solvents creates a major fire and explosion hazard because
the oxidizer can trigger spontaneous ignition of the organic
fuel.
Question 7
Which visual hazard warning standard uses a colored diamond
(Blue, Red, Yellow, White) to communicate chemical risks to
VERIFIED ANSWERS AND RATIONALES
(LATEST 2026 EDITION)
This comprehensive question practice exam package is
specifically engineered to guarantee a passing score on the
FDNY C-42 Certificate of Fitness examination. It features
verified multiple-choice questions covering critical fire
codes, material compatibility, personal protective equipment,
and emergency spill response protocols. Every question
includes a clear answer and a detailed, high-yield rationale,
making it the ultimate study tool to maximize your scores
and secure your certification.
Question 1
According to the NYC Fire Code, what is the maximum travel time
allowed for an employee to reach an emergency shower or
eyewash station from a hazardous corrosive handling area?
A) 30 seconds
B) 20 seconds
C) 10 seconds
D) 5 seconds
Answer: C
Rationale: The NYC Fire Code and ANSI Z358.1 standards
mandate that emergency eyewash and shower equipment
must be accessible within 10 seconds or less of walking
,travel time (approximately 55 feet) from the hazard, on an
unobstructed path on the same level.
Question 2
What formal chemical reaction hazard occurs when a strong acid
is directly and rapidly mixed with a concentrated base?
A) Endothermic sublimation
B) Exothermic neutralization
C) Catalytic ionization
D) Polymerization
Answer: B
Rationale: Mixing acids and bases results in a neutralization
reaction. This reaction is highly exothermic, meaning it
releases a significant amount of heat. If uncontrolled, it can
boil the liquid, melt plastic containers, and cause violent
splattering.
Question 3
Which of the following describes the core hazard of a Class 3
Oxidizer?
A) It causes skin burns on contact but does not support
combustion.
B) It causes a severe increase in the burning rate of combustible
materials with which it comes in contact.
C) It explodes spontaneously when exposed to regular ambient
air humidity.
D) It converts flammable liquids into inert gases.
,Answer: B
Rationale: Oxidizers readily yield oxygen or other oxidizing
gases, which severely intensifies and accelerates the
combustion rate of surrounding flammable or combustible
materials. Class 3 oxidizers cause a severe increase in the
burning rate.
Question 4
Under FDNY regulations, which document must be immediately
accessible to all employees handling hazardous chemicals in the
workplace?
A) The facility's corporate tax filing
B) The manufacturer's commercial retail catalog
C) Safety Data Sheets (SDS)
D) The local building occupancy certificate
Answer: C
Rationale: OSHA and FDNY regulations require Safety Data
Sheets (SDS) to be readily accessible to employees during all
work shifts. The SDS contains crucial details regarding
chemical properties, hazards, protective gear, and
emergency protocols.
Question 5
When storing containers of corrosive liquids, what structural
feature is required to prevent environmental contamination and
containment failure during a leak?
A) Absorbent wood shelving
B) Liquid-tight secondary containment
, C) Open floor drainage to public sewers
D) Elevated wire mesh racks without trays
Answer: B
Rationale: Secondary containment (such as trays, diking, or
containment pallets) is legally required for liquid hazardous
materials to collect leaks or spills from primary containers,
preventing them from spreading and causing reactions or
environmental damage.
Question 6
What is the primary operational reason why nitric acid must be
segregated from organic acids like acetic acid?
A) Nitric acid will freeze acetic acid solid.
B) Nitric acid acts as a powerful oxidizer that can react violently
and ignite organic compounds.
C) Acetic acid completely neutralizes the hazardous nature of
nitric acid.
D) They will vaporize into a non-toxic household cleaning solution.
Answer: B
Rationale: Nitric acid is not just a corrosive acid; it is also a
powerful oxidizer. Storing it next to organic acids or organic
solvents creates a major fire and explosion hazard because
the oxidizer can trigger spontaneous ignition of the organic
fuel.
Question 7
Which visual hazard warning standard uses a colored diamond
(Blue, Red, Yellow, White) to communicate chemical risks to
