What should I study for the hazmat endorsement?

Focus on the nine hazard classes, when placards are required and which to use, shipping papers and their placement, loading and segregation rules, and emergency response.

How many hazard classes are there?

Nine. They range from explosives (Class 1) to miscellaneous hazardous materials (Class 9), each with its own placards and handling rules.

What else is required besides passing the test?

A TSA security threat assessment, a fingerprint background check, is required before the endorsement is added to your license.

Hazmat Endorsement Study Guide: What to Know for the Test

Q: Do I need training before the hazmat test?

Yes. Since the ELDT rule, you must complete FMCSA-registered hazmat theory training, which can be done online, before taking the hazmat knowledge test.

Preparing for the hazmat endorsement means mastering the nine hazard classes, when and how to placard, shipping papers, safe loading and segregation, and emergency response. You must also complete FMCSA-registered hazmat theory training (which can be done online) before the test, and pass a TSA background check before the endorsement is issued.

The nine hazard classes

Hazardous materials are grouped into nine classes, and recognizing them is the foundation of the test:

Explosives
Gases (flammable, non-flammable, toxic)
Flammable liquids
Flammable solids
Oxidizers and organic peroxides
Toxic (poisonous) and infectious substances
Radioactive materials
Corrosives
Miscellaneous hazardous materials

Each class has associated placards, labels, and handling rules.

Placards: when and which

Placards are diamond-shaped warnings on the outside of the vehicle that tell everyone, including emergency responders, what hazard is aboard. The test covers when placards are required (based on the material and the amount) and which placard corresponds to which hazard class. Knowing the placarding tables is a core skill.

Shipping papers

Hazmat shipping papers describe the load and must be accurate and accessible. The test covers what information they contain, where they must be kept (within the driver's reach and clearly identifiable), and why they matter for emergency response. Proper markings and labels on packages are part of this too.

Loading, segregation, and securement

Some materials cannot be loaded together because they react dangerously. The test covers segregation rules, safe loading and unloading practices, and securing the load so it cannot shift or leak in transit.

Emergency response

If something goes wrong, a hazmat driver's job is to protect people first. The test covers what to do in a spill, leak, fire, or accident: warn others, keep people away, avoid making it worse, and communicate the hazard to responders using the shipping papers and placards.

Study tips

Learn the nine classes cold, then the placards that go with each.
Practice the placarding and segregation rules until they are automatic.
Take hazmat practice tests until you consistently score above 80%.
Start your TSA background check early, since it is the slowest step in getting the endorsement.

The bottom line

The hazmat test rewards knowing the nine classes, placarding, shipping papers, segregation, and emergency response. Complete your online hazmat theory training, drill practice questions to 80%+, and begin your TSA background check right away so nothing holds up your endorsement.

Once you have covered these topics, test yourself with the CDL hazmat practice test and review our strategies for how to pass the hazmat endorsement test. If you have not completed training yet, RoadCert's Hazmat ELDT theory is $18.99, and our hazmat endorsement guide walks through the full process.