Oklahoma Hazmat CDL Practice Test

This is a free 20-question practice test for the Hazmat portion of the Oklahoma Commercial Driver's License knowledge exam. Questions are pulled from a pool of 68 drawn from the AAMVA CDL Manual, which is the source document the Service Oklahoma Driver License Services uses to write its actual exam.

How it works: Click an answer. The correct choice highlights in green, and you'll see a short explanation. Aim for 85% or better before you sit for the real test in Oklahoma.

Question 1 of 20

Placards must be displayed on:

One side
Two sides
Three sides
All four sides of the vehicle

Correct. Placards are displayed on all four sides of the vehicle — front, back, and both sides.

Question 2 of 20

How many hazard classes are there?

Three
Five
Nine
Twelve

Correct. There are nine hazard classes: 1 explosives, 2 gases, 3 flammable liquids, 4 flammable solids, 5 oxidizers and organic peroxides, 6 toxic and infectious, 7 radioactive, 8 corrosive, 9 miscellaneous.

Question 3 of 20

A hazmat carrier with hazmat cargo must conduct security awareness training:

Once at hire
Once every 3 years for each driver
Annually
Never

Correct. PHMSA requires re-training every three years, including security awareness and the carrier's in-depth security plan if applicable.

Question 4 of 20

Subsidiary risk labels on a package indicate:

Additional hazards beyond the primary hazard
Just decoration
The price
The weight

Correct. Some materials have multiple hazards. The primary hazard is shown on the top-class label; subsidiary risks (e.g., toxic AND flammable) are shown on additional labels.

Question 5 of 20

Inhalation hazard placards (Division 6.1 PIH or Division 2.3) require:

Smaller placards
Subsidiary "INHALATION HAZARD" placards in addition to the primary placard
No placards
Only one placard

Correct. PIH (Poison Inhalation Hazard) materials require a primary hazard-class placard plus an "INHALATION HAZARD" subsidiary placard.

Question 6 of 20

A vehicle hauling explosives may not be parked within:

100 feet of an open fire, school, theater, or place where people gather
10 feet of any building
One block of a fire station
Any distance

Correct. Class 1 explosives have specific parking restrictions — at least 300 feet from open fires; never near schools, theaters, or places where people gather.

Question 7 of 20

When you stop at a railroad crossing in a placarded hazmat vehicle, you must stop:

On the tracks
Between 15 and 50 feet from the nearest rail
Anywhere
Only if a train is visible

Correct. Placarded hazmat vehicles must stop at every railroad crossing 15 to 50 feet from the nearest rail. Look and listen for trains.

Question 8 of 20

You must not transport a vehicle that:

Has Class 1 explosives and is leaking, or any vehicle whose hazmat is leaking
Has fresh paint
Is over weight by 50 lbs
Is white

Correct. Never transport a leaking hazmat package. Secure the scene, notify authorities and the carrier, follow the carrier's instructions on disposition.

Question 9 of 20

When transporting hazmat, you must check the cargo every:

Mile
100 miles
150 miles or 3 hours, plus changes of duty status
500 miles

Correct. Federal cargo securement: check at the start, then every 150 miles or 3 hours of driving, plus every change of duty status.

Question 10 of 20

When parking a placarded hazmat vehicle at a truck stop overnight, you should:

Park in a designated hazmat parking area, follow attendance rules for explosives, never block traffic
Park behind the fuel pumps
Park in the entrance
Park anywhere

Correct. Use designated hazmat parking. Explosives and certain other materials require attended parking; review the carrier's policy and federal rules.

Question 11 of 20

You discover a leak in a Class 3 (flammable liquid) shipment. You should:

Continue driving until you find a safe place
Stop, secure the area, notify emergency services, do not transfer cargo on the road, do not move the vehicle further than necessary
Drive faster to deliver the load
Open the placards

Correct. Stop in a safe location, secure the area, call 911, and notify your dispatcher. Do not transfer cargo by the side of the road.

Question 12 of 20

A leaking package of hazmat:

Should be immediately driven to the destination
Must not be transported; secure and report
Should be wrapped in plastic
Should be ignored

Correct. Never transport a leaking package. Secure the area, report to the carrier, contact emergency services if the leak poses immediate danger.

Question 13 of 20

Bulk packaging of certain corrosives requires:

No special markings
Display of the proper shipping name on each side and the four-digit ID number on each side and end
Only one placard
Painted red

Correct. Bulk packaging of corrosives, like other hazmat, requires shipping name on the sides and ID-number marking on each side and end.

Question 14 of 20

Hazard Class 8 is:

Flammable solids
Corrosives
Radioactive
Gases

Correct. Class 8 is corrosive materials — sulfuric acid, sodium hydroxide, hydrochloric acid, etc.

Question 15 of 20

When carrying hazmat through a state or local jurisdiction with route restrictions, you must:

Comply with the restrictions
Choose the shortest route
Take the highway always
Disregard local rules

Correct. State and local hazmat route restrictions are enforceable. Plan routes that comply with restrictions and avoid prohibited tunnels and bridges.

Question 16 of 20

Carrying a hazmat shipment without the required shipping paper:

Is allowed if you remember the cargo
Is a violation; the shipping paper must be present and accessible
Is allowed if you have a phone
Has no consequence

Correct. Operating without proper shipping papers is a regulatory violation and dangerous — emergency responders rely on the paper to identify materials.

Question 17 of 20

When unloading flammable liquids from a cargo tank, the driver should:

Bond and ground the tank to the receiving container to prevent static-spark ignition
Disconnect the ground
Smoke
Run the engine

Correct. Bonding and grounding equalizes electrical potential between the tank and receiving container, preventing static-spark ignition during product transfer.

Question 18 of 20

When a hazmat shipment crosses international borders:

Documentation may need to comply with both US and Canadian/Mexican regulations
No special documentation is needed
Only US regulations apply
Only foreign regulations apply

Correct. Cross-border hazmat may require documentation in compliance with both jurisdictions, plus customs paperwork.

Question 19 of 20

Hazmat marking on a non-bulk package includes:

Proper shipping name and UN/NA number
Just the weight
Just the destination
Color only

Correct. Non-bulk markings include the proper shipping name and UN/NA identification number, plus consignor/consignee information.

Question 20 of 20

The Emergency Response Guidebook (ERG) is used to:

Plan routes
Look up the four-digit hazmat ID number to find emergency response procedures
Calculate fuel cost
Find truck stops

Correct. The ERG cross-references the four-digit ID number from the placard or shipping paper to a guide page with isolation distance, response procedures, and first aid.

About the Oklahoma Hazmat exam

Most states administer 30 Hazmat questions and require 80% to pass. The exam covers hazard classes, the shipping paper, placards and labels, loading and unloading, driving and parking rules, emergency response, and the Emergency Response Guidebook (ERG).

The Service Oklahoma Driver License Services follows the federal CDL standards established by FMCSA. To earn the Hazmat credential, you must answer at least 80% of the questions correctly. Many candidates score lower the first time because the test pulls from a large pool — refreshing this page will give you a different mix of questions, drawn from the same authoritative source.

Want more practice? Try the full Hazmat question bank or browse all Oklahoma CDL practice tests.