FDNY C42 Storage and Handling of Corrosives
and Oxidizers 2026 Exam Practice Questions –
Questions
Verified Answers with Expert Rationales | 2026 Edition
Question 1:
Which of the following best defines a corrosive material according to the
FDNY C-42 context?
A) A substance that rapidly oxidizes organic material
B) A material that destroys living tissue and/or materials by chemical action
C) A compressed gas that is flammable
D) A liquid with a flash point below 100°F
*Answer: * B) A material that destroys living tissue and/or materials by
chemical action
*Rationale: * Corrosives cause visible destruction or irreversible damage to
living tissue and attack metals and other materials through chemical
reaction.
Question 2:
Which class best describes oxidizing agents?
A) Substances that react violently with water
B) Substances that yield oxygen to promote combustion of other materials
C) Substances with a pH less than 2
D) Substances that are always gases at room temperature
*Answer: * B) Substances that yield oxygen to promote combustion of
other materials
,*Rationale: * Oxidizers provide oxygen or other oxidizing substances that
increase the burning rate and intensity of combustible materials.
Question 3:
Which permit threshold requires an FDNY permit for storage of corrosive
liquids?
A) 1 gallon
B) 5 gallons
C) 55 gallons
D) Any quantity
*Answer: * C) 55 gallons
*Rationale: * The FDNY requires a permit for the storage of 55 gallons or
more of corrosive liquids.
Question 4:
What is the primary purpose of a Certificate of Fitness issued by the FDNY?
A) To allow construction workers on a site
B) To certify fire department employees
C) To ensure personnel are qualified to handle specific hazardous materials
safely
D) To provide insurance coverage
*Answer: * C) To ensure personnel are qualified to handle specific
hazardous materials safely
*Rationale: * The Certificate of Fitness ensures that individuals have
demonstrated the knowledge and competency required to safely handle,
,store, and supervise hazardous materials in compliance with FDNY
regulations.
Question 5:
A material that causes visible destruction or irreversible alterations in living
tissue by chemical action is classified as a:
A) Flammable liquid
B) Corrosive
C) Oxidizer
D) Toxic substance
*Answer: * B) Corrosive
*Rationale: * This is the defining characteristic of corrosive materials
according to FDNY regulations.
Question 6:
Corrosive substances are typically classified as:
A) Flammable liquids
B) Acids and bases
C) Explosives
D) Oxidizing agents
*Answer: * B) Acids and bases
*Rationale: * Corrosives primarily include acids and bases, which are capable
of destroying living tissue and materials through chemical action.
, Question 7:
Oxidizers are defined as substances that:
A) React violently with water
B) Yield oxygen that promotes combustion of other materials
C) Have a pH less than 2
D) Are always gases at room temperature
*Answer: * B) Yield oxygen that promotes combustion of other
materials
*Rationale: * Oxidizers provide oxygen or other oxidizing substances that
increase the burning rate and intensity of combustible materials.
Question 8:
According to FDNY regulations, which of the following is the primary
hazard associated with oxidizers?
A) Flammability
B) Reaction with combustible materials
C) Corrosion of metals
D) Explosive vapor formation
*Answer: * B) Reaction with combustible materials
*Rationale: * Oxidizers can cause or enhance combustion of other materials,
even without an ignition source.
Question 9:
Corrosive substances primarily cause damage by:
and Oxidizers 2026 Exam Practice Questions –
Questions
Verified Answers with Expert Rationales | 2026 Edition
Question 1:
Which of the following best defines a corrosive material according to the
FDNY C-42 context?
A) A substance that rapidly oxidizes organic material
B) A material that destroys living tissue and/or materials by chemical action
C) A compressed gas that is flammable
D) A liquid with a flash point below 100°F
*Answer: * B) A material that destroys living tissue and/or materials by
chemical action
*Rationale: * Corrosives cause visible destruction or irreversible damage to
living tissue and attack metals and other materials through chemical
reaction.
Question 2:
Which class best describes oxidizing agents?
A) Substances that react violently with water
B) Substances that yield oxygen to promote combustion of other materials
C) Substances with a pH less than 2
D) Substances that are always gases at room temperature
*Answer: * B) Substances that yield oxygen to promote combustion of
other materials
,*Rationale: * Oxidizers provide oxygen or other oxidizing substances that
increase the burning rate and intensity of combustible materials.
Question 3:
Which permit threshold requires an FDNY permit for storage of corrosive
liquids?
A) 1 gallon
B) 5 gallons
C) 55 gallons
D) Any quantity
*Answer: * C) 55 gallons
*Rationale: * The FDNY requires a permit for the storage of 55 gallons or
more of corrosive liquids.
Question 4:
What is the primary purpose of a Certificate of Fitness issued by the FDNY?
A) To allow construction workers on a site
B) To certify fire department employees
C) To ensure personnel are qualified to handle specific hazardous materials
safely
D) To provide insurance coverage
*Answer: * C) To ensure personnel are qualified to handle specific
hazardous materials safely
*Rationale: * The Certificate of Fitness ensures that individuals have
demonstrated the knowledge and competency required to safely handle,
,store, and supervise hazardous materials in compliance with FDNY
regulations.
Question 5:
A material that causes visible destruction or irreversible alterations in living
tissue by chemical action is classified as a:
A) Flammable liquid
B) Corrosive
C) Oxidizer
D) Toxic substance
*Answer: * B) Corrosive
*Rationale: * This is the defining characteristic of corrosive materials
according to FDNY regulations.
Question 6:
Corrosive substances are typically classified as:
A) Flammable liquids
B) Acids and bases
C) Explosives
D) Oxidizing agents
*Answer: * B) Acids and bases
*Rationale: * Corrosives primarily include acids and bases, which are capable
of destroying living tissue and materials through chemical action.
, Question 7:
Oxidizers are defined as substances that:
A) React violently with water
B) Yield oxygen that promotes combustion of other materials
C) Have a pH less than 2
D) Are always gases at room temperature
*Answer: * B) Yield oxygen that promotes combustion of other
materials
*Rationale: * Oxidizers provide oxygen or other oxidizing substances that
increase the burning rate and intensity of combustible materials.
Question 8:
According to FDNY regulations, which of the following is the primary
hazard associated with oxidizers?
A) Flammability
B) Reaction with combustible materials
C) Corrosion of metals
D) Explosive vapor formation
*Answer: * B) Reaction with combustible materials
*Rationale: * Oxidizers can cause or enhance combustion of other materials,
even without an ignition source.
Question 9:
Corrosive substances primarily cause damage by:
