25 realistic Hazardous Materials practice questions for Oklahoma CDL applicants. Required for: Drivers transporting placarded hazardous materials. Official test: 30 questions, 24 correct to pass.
Question 1 of 25 · HazMat Basics
What is "hazard class"?
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A.
A grouping of materials by hazard type
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B.
A type of placard
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C.
A required driving license
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D.
A type of HazMat trailer
Correct answer: A.
There are nine hazard classes that group materials with similar dangers.
Question 2 of 25 · Emergencies
What is the first thing you should do if your HazMat load catches fire?
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A.
Pull over, away from buildings or vehicles, then call 911
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B.
Drive to the nearest hospital
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C.
Continue to destination
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D.
Try to put it out with snow
Correct answer: A.
Stop in a safe place, away from people and buildings, then notify emergency services.
Question 3 of 25 · Loading
What does "blasting agents" refer to?
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A.
Materials used to detonate explosives
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B.
A class of explosives sensitive to ignition
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C.
Cleaning agents
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D.
Aerosol propellants
Correct answer: A.
Blasting agents are materials designed to be set off using a detonator.
Question 4 of 25 · Loading
When loading or unloading HazMat:
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A.
Set the parking brake
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B.
Be sure the cargo is properly braced
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C.
Stay close to the vehicle
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D.
All of the above
Correct answer: D.
Keep the brakes set, secure cargo, and remain on alert during loading and unloading.
Question 5 of 25 · Shipping Papers
What information must a HazMat driver have on the bills of lading?
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A.
Total quantity by weight or volume
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B.
Number and type of packages
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C.
Shipping name and hazard class
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D.
All of the above
Correct answer: D.
All of these must be included for HazMat shipments.
Question 6 of 25 · Shipping Papers
Which is true regarding HazMat shipping papers tabs?
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A.
They must be tabbed or be the first paper
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B.
They are filed alphabetically only
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C.
They are not required to be visible
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D.
They must be in a sealed envelope
Correct answer: A.
HazMat papers must be the top paper or tabbed to be readily identifiable.
Question 7 of 25 · Emergencies
When a HazMat package leaks, you should:
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A.
Move it to a safe area
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B.
Secure the area and call for help
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C.
Continue the trip
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D.
Place it in the trailer's rear
Correct answer: B.
Don't move leaking packages. Secure the area and contact qualified responders.
Question 8 of 25 · CDL Rules
What does the letter "H" represent on a CDL?
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A.
Hazardous materials endorsement
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B.
Heavy vehicle endorsement
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C.
Highway driving endorsement
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D.
Hauling endorsement
Correct answer: A.
The H endorsement allows a CDL holder to transport placarded hazardous materials.
Question 9 of 25 · Emergencies
Drivers must report HazMat incidents to:
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A.
The local newspaper
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B.
Carrier and law enforcement, then the National Response Center
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C.
No one — drivers are not responsible
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D.
The shipper only
Correct answer: B.
Notify your carrier and local responders, then call the National Response Center if reportable.
Question 10 of 25 · Parking
When can a HazMat shipment be left unattended?
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A.
Whenever the driver leaves the vehicle
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B.
Only in safe locations such as a carrier facility
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C.
Anywhere with a sign
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D.
Only on private roads
Correct answer: B.
HazMat must be attended unless parked at a carrier facility or other approved location.
Question 11 of 25 · Shipping Papers
Where can drivers find emergency contact information for the materials they're hauling?
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A.
On the placards
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B.
In the shipping papers
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C.
On the trailer doors
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D.
In the glove box
Correct answer: B.
A 24-hour emergency contact number must appear on the shipping papers.
Question 12 of 25 · Placards
Which of these is required if a vehicle's placards are missing or destroyed?
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A.
Placards must be replaced before continuing
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B.
Drivers can continue without placards
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C.
Drivers must call OSHA
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D.
Drivers must wait until next shipping point
Correct answer: A.
Replace missing or damaged placards immediately before continuing.
Question 13 of 25 · Placards
Green placards usually indicate:
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A.
Compressed gases (non-flammable)
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B.
Explosives
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C.
Poisons
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D.
Corrosives
Correct answer: A.
Green placards usually indicate non-flammable compressed gases.
Question 14 of 25 · HazMat Driving
Drivers transporting Division 1.1, 1.2, or 1.3 explosives may NOT:
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A.
Take a route that goes through tunnels prohibiting explosives
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B.
Refuel at any station
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C.
Travel during business hours
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D.
Cross any state line
Correct answer: A.
Avoid tunnels and routes prohibiting explosives. Use only approved routes.
Question 15 of 25 · Shipping Papers
Where do you find a list of names of hazardous wastes?
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A.
EPA Hazardous Waste Manifest
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B.
Driver manual
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C.
Local newspaper
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D.
CDL handbook
Correct answer: A.
Hazardous waste appears on the EPA hazardous waste manifest, signed by both shipper and driver.
Question 16 of 25 · Placards
What does "subsidiary hazard class" mean?
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A.
A secondary hazard a material poses
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B.
A backup placard
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C.
A small package
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D.
A vehicle accessory
Correct answer: A.
Some materials have a primary and a subsidiary hazard class for additional risks.
Question 17 of 25 · HazMat Driving
What is the speed limit when transporting HazMat through a tunnel?
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A.
Tunnel speed limit minus 10 mph
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B.
Posted limit
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C.
No speed limit applies to HazMat
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D.
Posted speed unless lower limit is posted for HazMat
Correct answer: D.
Follow posted limits; lower limits often apply specifically to HazMat in tunnels.
Question 18 of 25 · HazMat Driving
When transporting Class 1 explosives, the driver must:
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A.
Park anywhere convenient
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B.
Have a written route plan and follow it
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C.
Drive only at night
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D.
Drive only on local roads
Correct answer: B.
Drivers must have a route plan and avoid populated areas where possible.
Question 19 of 25 · Placards
Which of these placards has a yellow background?
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A.
Flammable solids
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B.
Oxidizers
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C.
Corrosives
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D.
Radioactive
Correct answer: B.
Yellow background placards typically indicate oxidizers.
Question 20 of 25 · Security
Drivers should report any HazMat shipment that:
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A.
Appears to be tampered with
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B.
Has missing or damaged placards
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C.
Has a strong odor or evidence of leakage
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D.
All of the above
Correct answer: D.
Always report any sign of tampering, damaged placards, or leak evidence.
Question 21 of 25 · HazMat Driving
When transporting HazMat over long distances, drivers should:
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A.
Stay alert, take rest breaks, and inspect the load regularly
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B.
Drive at maximum speed limit
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C.
Skip rest stops to save time
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D.
Avoid highways
Correct answer: A.
Stay alert with regular rest breaks; inspect cargo at every stop.
Question 22 of 25 · Placards
What does the placard table tell you?
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A.
Which placards are required for which materials and quantities
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B.
Vehicle dimensions
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C.
Highway routes
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D.
Loading dock procedures
Correct answer: A.
The placarding table sets the placard rules based on hazard class and amount.
Question 23 of 25 · Shipping Papers
Where can a driver find information about which HazMat are flammable?
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A.
Hazardous Materials Table
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B.
CDL test only
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C.
Engine manual
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D.
Driver license documents
Correct answer: A.
The DOT Hazardous Materials Table classifies materials and lists handling requirements.
Question 24 of 25 · Emergency Equipment
Are flares allowed when stopped near a HazMat leak?
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A.
Yes, always use flares
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B.
No, do not use flares near a HazMat leak — use reflective triangles
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C.
Only with permission
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D.
Only at night
Correct answer: B.
Open flames are dangerous near leaks. Use reflective triangles instead.
Question 25 of 25 · HazMat Basics
How many hazard classes are there?
Correct answer: C.
There are nine UN hazard classes used for HazMat transportation.
About the Hazardous Materials Test
The Hazardous Materials (HazMat) test covers the rules for transporting materials that pose a risk to health, safety, and property. Topics include the hazardous materials table, shipping papers, marking, labeling, placarding, loading and unloading, bulk packaging, driving and parking rules, communications, emergencies, and hazardous materials regulations enforced by the U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration. A federal Transportation Security Administration (TSA) background check is also required.
The Oklahoma Department of Public Safety — Driver License Services administers this knowledge test as part of its commercial driver license program. To earn the HazMat Endorsement (H) on your Oklahoma CDL, you need to score at least 24 out of 30 on the official version.
Topics covered on this practice test
- Shipping Papers: 5 questions
- Placards: 5 questions
- HazMat Driving: 4 questions
- Emergencies: 3 questions
- HazMat Basics: 2 questions
- Loading: 2 questions
- CDL Rules: 1 question
- Parking: 1 question
- Security: 1 question
- Emergency Equipment: 1 question
How to use this practice test
- Read each question carefully. CDL questions are written precisely — small wording differences matter.
- Click "Show Answers & Explanations" only after answering every question. Don't peek mid-test.
- Read the explanation for every question, even ones you got right. The reasoning is more important than the answer.
- Repeat the test until you score 100%. The questions are deterministic per state, so you can track your improvement over multiple sessions.
- Move on to the other endorsement tests for Oklahoma until you're ready for the official exam.
Tips specific to the Hazardous Materials test
HazMat is the longest knowledge test (30 questions) and adds a Transportation Security Administration (TSA) background check. Most candidates struggle with placard colors, the segregation table, shipping paper requirements, and emergency response procedures. Use the official Emergency Response Guidebook (ERG) alongside this practice set.