Hazmat CDL Practice Test: Sample Questions and What to Study
The hazmat endorsement knowledge test covers loading and unloading rules, placarding, shipping papers, and the nine hazmat classes, and most states set the passing score at 80 percent. Getting the endorsement also requires a separate federal background check, the TSA Security Threat Assessment, which includes fingerprinting and is not part of the written exam.
CDL is the name of a real credential issued by state driver-licensing agencies, and this page is not affiliated with FMCSA, TSA, or any state DMV. The exact question count and passing threshold for the hazmat knowledge test are set by each state, not by a single federal standard, so treat the numbers below as a close model, not a guarantee for your state. We wrote every practice question here from scratch, based on federal hazmat regulations, not copied from any exam bank.
What does the hazmat endorsement knowledge test actually cover?
The test checks whether you understand the rules for safely loading, transporting, and unloading hazardous materials, not just memorized trivia. Under 49 CFR 383.121, applicants must show knowledge drawn from the federal hazmat regulations in 49 CFR parts 171 through 178 and 397, covering topics like hazard classification, package marking, placarding, shipping paper preparation, and driving and parking restrictions near open flame or in tunnels (Cornell LII, 49 CFR 383.121).
In practice, that breaks into a handful of study areas: the nine hazard classes and how to identify them, when a load needs placards versus just labels, what has to be on the shipping papers and where the driver keeps them, and the handful of situations (fueling, smoking, tunnels, fire) where hazmat drivers follow stricter rules than everyone else.
How is the TSA background check different from the knowledge test?
The TSA check is a separate federal security screening, not a study section, and you cannot pass your way around it. Anyone applying for, renewing, or transferring a hazmat endorsement must complete a Security Threat Assessment through TSA’s Hazardous Materials Endorsement Threat Assessment Program, which includes submitting fingerprints for an FBI criminal history check (TSA, Hazmat Endorsement).
TSA’s current fee for a new applicant’s Security Threat Assessment is $86.50, and the clearance is valid for five years before the driver has to submit new fingerprints and go through the process again (TSA.gov, accessed July 2026, see link above). Some states, including Pennsylvania, run the enrollment through the state’s own driver-licensing agency instead of a TSA application center, so check your state DMV’s hazmat page for the exact steps before you schedule anything.
How many questions are on the hazmat test, and what score do you need?
Most states use 30 multiple-choice questions for the hazmat knowledge test and require 80 percent correct to pass, but the exact count is set state by state, not by one federal rule. The Texas Department of Public Safety’s CDL manual, for example, sets the hazmat knowledge test at 30 questions, and an applicant needs 24 correct answers (80 percent) to pass (Texas DPS, Commercial Driver License). Pennsylvania’s Commercial Driver’s Manual requires hazmat endorsement holders to retake and pass the Hazardous Materials Knowledge Test, plus a new Security Threat Assessment, every four years to recertify (PennDOT Publication 223).
Because states set their own question banks and vendor platforms, don’t assume your state matches Texas exactly. Confirm the count and passing score on your own state’s CDL manual page before test day.
What are the nine hazmat classes you need to know?
Every hazardous material sold or transported in the US falls into one of nine numbered classes, and the test expects you to match materials to their class on sight. This table doubles as your quick-reference sheet.
| Class | Name | Example |
|---|---|---|
| 1 | Explosives (divisions 1.1 to 1.6) | Fireworks, blasting agents |
| 2 | Gases (2.1 flammable, 2.2 non-flammable, 2.3 toxic) | Propane, oxygen, chlorine |
| 3 | Flammable liquids | Gasoline, diesel additives |
| 4 | Flammable solids | Matches, magnesium |
| 5 | Oxidizers and organic peroxides | Ammonium nitrate, pool chlorine |
| 6 | Toxic and infectious substances | Pesticides, medical waste |
| 7 | Radioactive materials | Medical isotopes |
| 8 | Corrosive materials | Battery acid, drain cleaner |
| 9 | Miscellaneous dangerous goods | Lithium batteries, dry ice |
When does a load need placards?
A load needs placards once it crosses a weight threshold, except for the highest-risk materials, which always need placards no matter how little you’re carrying. Under 49 CFR 172.504, most hazardous materials (Table 2 in the regulation) require placards once a vehicle carries 1,001 pounds or more of a single hazard class in non-bulk packaging. A shorter list of higher-risk materials (Table 1), including Division 1.1 to 1.3 explosives, Division 2.3 toxic gas, and Division 4.3 water-reactive solids, require placards at any quantity (eCFR, 49 CFR 172.504).
The test will hand you a scenario (“you’re carrying 1,500 pounds of a Table 2 flammable liquid”) and expect you to apply the threshold, not recite it. Practice doing the math, not just reading the rule.
What has to be on the shipping papers?
Shipping papers must identify the material by its UN or NA number, proper shipping name, hazard class, and packing group, plus the total quantity. Under 49 CFR 172.202, the description on the shipping paper must include the identification number, the proper shipping name, and the hazard class or division exactly as they appear in the hazmat table, along with the packing group in Roman numerals where one applies (Cornell LII, 49 CFR 172.202). The papers also need an emergency contact phone number that’s staffed and knowledgeable about the shipment.
While driving, the papers stay within the driver’s immediate reach, either in a pouch on the driver’s door or visible on the seat, never buried in the sleeper or glovebox. When the driver leaves the vehicle, the papers go on the driver’s seat or in the driver’s door pouch, so emergency responders can find them fast.
Run through timed scenario questions like these in the CDL Practice Hub hazmat practice quiz before test day, since recognizing a weight threshold or a shipping-paper gap under time pressure is a different skill than reading the rule once.
Sample hazmat CDL practice questions
These are original questions we wrote from the federal hazmat regulations, not copied from any state or third-party test bank. Use them to check your understanding, not to guess at a real exam’s wording.
-
Which hazard class covers gasoline and other flammable liquids? Class 3. Flammable liquids are grouped by flash point, and gasoline, along with most fuel additives, falls into this class.
-
A truck is carrying 1,500 pounds of a Table 2 flammable solid in non-bulk packaging. Does it need placards? Yes. Table 2 materials require placards once the load reaches 1,001 pounds of a single hazard class, so 1,500 pounds triggers the requirement.
-
Which hazard class covers corrosive materials like battery acid? Class 8. Corrosive materials can destroy skin tissue or corrode metal on contact, and the class 8 placard is black and white with a distinct symbol.
-
True or false: A carrier can skip placards on Division 1.1 explosives if the load is under 1,001 pounds. False. Division 1.1 explosives are a Table 1 material, and Table 1 materials require placards at any quantity, with no weight exemption.
-
What must appear on the shipping papers for a hazmat shipment, besides the shipper’s name? The proper shipping name, the UN or NA identification number, the hazard class or division, the packing group where applicable, the total quantity, and an emergency response phone number.
-
Where should a driver keep shipping papers while the vehicle is moving? Within immediate reach, either in a pouch mounted on the driver’s door or visible on the driver’s seat, so the papers are accessible without unbuckling or searching the cab.
-
Which class covers radioactive materials such as medical isotopes? Class 7. Radioactive shipments follow their own labeling and placarding rules separate from the other eight classes.
-
A shipment includes 500 pounds of Division 2.3 toxic gas. Does the load need placards? Yes. Division 2.3 toxic gas is a Table 1 material, so it requires placards regardless of the quantity carried, unlike Table 2 materials that have a weight threshold.
-
What federal screening applies to hazmat endorsement holders beyond the written knowledge test? The TSA Security Threat Assessment, a fingerprint-based FBI criminal history check administered by TSA, separate from the state’s knowledge test.
-
Which hazard class covers oxidizers such as ammonium nitrate? Class 5. Oxidizers can intensify a fire by supplying oxygen, and they’re kept in a separate class from flammable materials for that reason.
If a study guide covers every one of these topics in one place, that’s the CDL Practice Hub hazmat CDL study guide, built around the same federal sections cited above rather than a generic question dump.
FAQ
Do I need a hazmat endorsement if I only haul small quantities? It depends on the material and quantity. Table 1 materials, like Division 1.1 explosives or Division 2.3 toxic gas, require an endorsement at any quantity, while most other materials only trigger the requirement once the load needs placarding under the weight thresholds in 49 CFR 172.504.
How long does the TSA background check take? TSA recommends applying at least 60 days before you need a decision, since processing can run past 45 days during high-demand periods. Fingerprinting and document review both happen at an in-person application center or, in some states, at the state DMV.
Can I retake the hazmat knowledge test if I fail? Yes, in most states, though some require a waiting period or an additional fee before you can retest. Check your specific state CDL manual for its retest rules, since they vary.
Does the hazmat endorsement expire? Yes. Most states tie the hazmat endorsement to the five-year TSA Security Threat Assessment cycle, though Pennsylvania requires recertification of the knowledge test every four years. Confirm your state’s renewal cycle before your current endorsement lapses.
Is the hazmat test harder than the general knowledge test? It’s shorter (commonly 30 questions versus 50 for general knowledge) but denser, since it packs federal regulatory detail like placarding thresholds and shipping paper rules into fewer questions. Most drivers find it takes more focused study time per question than the general knowledge test.