Missouri Hazmat CDL Practice Test

This is a free 20-question practice test for the Hazmat portion of the Missouri 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 Missouri Department of Revenue Driver License Bureau 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 Missouri.

Question 1 of 20

Hazardous materials are products that:

Are heavier than normal cargo
Pose a risk to health, safety, or property during transportation
Can only be hauled at night
Require a special trailer color

Correct. Hazardous materials (hazmat) are products that pose a risk to health, safety, or property during transportation. Hazmat regulations are codified in 49 CFR.

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

Hazard Class 1 is:

Flammable liquids
Explosives
Corrosives
Radioactive materials

Correct. Class 1 covers explosives, divided into divisions 1.1 through 1.6 by mass-explosion and projection hazard.

Question 4 of 20

When loading a vehicle with hazardous materials, you should:

Set the parking brake, chock the wheels, turn off the engine
Leave the engine running
Smoke if outside the cab
Skip the brake check

Correct. Set the parking brake, chock wheels of cargo tank vehicles, and shut off the engine before loading or unloading flammables.

Question 5 of 20

You may use a flame to check for hazmat leaks:

When you have a respirator
Never — never use any flame near hazmat
Only at night
Only with permission

Correct. Never use a flame to check anything near hazmat. Use a flashlight or other intrinsically safe light.

Question 6 of 20

The Hazmat (H) endorsement requires:

Only a knowledge test
A knowledge test plus a TSA Threat Assessment background check
Just a fee
A skills test only

Correct. Hazmat applicants pass a knowledge test and complete the TSA Threat Assessment (HME), which involves fingerprints and an FBI background check.

Question 7 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 8 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.

Question 9 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 10 of 20

The Hazardous Materials Table (HMT) lists:

Only flammable liquids
Each hazardous material with its proper shipping name, hazard class, ID number, packing group, and required label
Only items shipped by air
Only items shipped by truck

Correct. The HMT in 49 CFR §172.101 lists every hazardous material with its proper shipping name, hazard class, identification number, packing group, label requirements, and special provisions.

Question 11 of 20

The shipping paper for hazmat must include:

Only the destination
Proper shipping name, hazard class, ID number with UN/NA prefix, packing group, total quantity, and emergency contact
Only the weight
Only the carrier name

Correct. A complete shipping paper includes proper shipping name, hazard class or division, UN/NA ID number, packing group (where applicable), total quantity and unit, and a 24-hour emergency contact.

Question 12 of 20

When in the cab with the engine running, the hazmat shipping paper must be:

In the trailer
Within the driver's reach — clipped on the driver's door clip or on the driver's seat
In the glove compartment
In the trunk

Correct. When in the seat with the engine running, keep shipping papers within reach (driver-side door clip or on the seat). When out of the vehicle, leave on the seat or in the door pouch.

Question 13 of 20

When refueling a hazmat-loaded vehicle:

Leave the engine running
Turn off the engine, do not smoke, and someone must control the fueling process
Smoke if you are far enough away
It does not matter

Correct. Engine off, no smoking within 25 feet of the vehicle being fueled, and someone must be in control of the fueling at the nozzle.

Question 14 of 20

A driver is required to carry an ERG (or equivalent) when:

Driving any commercial vehicle
Transporting any quantity of hazardous materials
Only when hauling explosives
Only on weekends

Correct. Whenever hazmat is being transported, the driver must have access to current ERG information for the materials in question.

Question 15 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 16 of 20

A hazmat driver must complete which special training?

General awareness, function-specific, safety, security awareness, and in-depth security if a security plan is required
Forklift training
Basic first aid only
Defensive driving only

Correct. PHMSA requires general awareness, function-specific, safety, security awareness, and in-depth security training (when a security plan applies). Carriers document and re-train every three years.

Question 17 of 20

Hazard Class 3 is:

Flammable liquids
Explosives
Toxic substances
Radioactive

Correct. Class 3 is flammable liquids — gasoline, diesel, ethanol, alcohols, etc.

Question 18 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 19 of 20

A vehicle that has been transporting hazmat may need to be:

Decontaminated and re-placarded as required after unloading
Painted
Sold
Inspected by USCG

Correct. After unloading, the vehicle may need decontamination depending on the cargo. Placards may need to be removed unless residue still requires them.

Question 20 of 20

Hazard Class 8 is:

Flammable solids
Corrosives
Radioactive
Gases

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

About the Missouri 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 Missouri Department of Revenue Driver License Bureau 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 Missouri CDL practice tests.