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TX · H Endorsement

Texas Hazardous Materials CDL Practice Test

Below are 25 exam-style questions for the Texas Hazardous Materials CDL knowledge test, modeled on the FMCSA-aligned content used by the Texas Department of Public Safety. Try to answer each question on your own before reading the answer key directly under it. The questions and answer choices are shuffled deterministically per state and endorsement, so the order will stay the same on repeat visits — that lets you genuinely measure your improvement.

Heads up: this is a study tool, not a graded exam. Cover the answer with your hand or a sheet of paper for an honest practice run, then re-read the explanations for any questions you missed. Aim for 22 out of 25 or better, three times in a row, before scheduling the real exam.
Question 1 of 25
Cargo tank trucks must be inspected:
  • A Before each trip and at every stop
  • B When the tank is full
  • C Annually only
  • D Once per year by federal officials
Correct answer: A
Tanks must be inspected for leaks, valves, and integrity before and during the trip.
Question 2 of 25
A "subsidiary risk" placard means:
  • A A placard for a small load only
  • B A placard for the trailer interior
  • C A placard for state-only highways
  • D A placard for an additional hazard the material poses besides the primary hazard
Correct answer: D
Some materials present more than one hazard; the secondary placard alerts responders to it.
Question 3 of 25
Some hazmat loads require a special endorsement on top of the H endorsement:
  • A X (combination of H and N for tank vehicles carrying hazardous materials)
  • B A separate trailer license
  • C A pilot car
  • D A medical card upgrade
Correct answer: A
X combines Hazmat (H) and Tank (N) for drivers who haul hazardous materials in tank vehicles.
Question 4 of 25
Hazardous materials regulations are intended to:
  • A Reduce fuel use
  • B Provide tax revenue
  • C Help drivers move faster
  • D Communicate the risk, contain the materials, and protect the public
Correct answer: D
The Hazardous Materials Regulations focus on communicating the risk (placards, papers), containment, and public safety.
Question 5 of 25
When a hazmat load includes Class 3 (flammable liquids) and Class 1 (explosives), you should:
  • A Load them in the same compartment
  • B Cover the explosives with the liquids
  • C Always keep them together
  • D Check the segregation table — many combinations are forbidden
Correct answer: D
The segregation table in 49 CFR §177.848 forbids many combinations; check before loading.
Question 6 of 25
A driver must inspect hazmat shipping papers for:
  • A Price only
  • B Color of packaging
  • C Proper shipping name, hazard class, ID number, and required emergency information
  • D Driver's name
Correct answer: C
Shipping papers must be complete and correct before transport.
Question 7 of 25
Cargo tanks loaded with flammable liquids must be:
  • A Bonded and grounded during loading and unloading
  • B Inspected once a year only
  • C Loaded only at night
  • D Loaded only by the receiver
Correct answer: A
Bonding equalizes electrical potential to prevent static spark; grounding sends static to earth.
Question 8 of 25
You must keep hazmat shipping papers separate from other documents:
  • A Only on long trips
  • B Yes — they should be readily identifiable for emergency responders
  • C No — mix them in with other paperwork
  • D Only if the receiver requests it
Correct answer: B
Shipping papers are tabbed or kept on top of stack for quick identification.
Question 9 of 25
Drivers carrying hazmat must:
  • A Have current hazmat training
  • B All of the above
  • C Carry shipping papers and ERG
  • D Have current TSA security threat assessment
Correct answer: B
All three are required for placarded hazmat operations.
Question 10 of 25
A common hazardous material identification number begins with:
  • A UN or NA followed by four digits
  • B A state two-letter code
  • C A barcode only
  • D A serial number
Correct answer: A
UN (United Nations) or NA (North America) plus four digits identifies the material in the Hazardous Materials Table and the ERG.
Question 11 of 25
A driver of a placarded vehicle must:
  • A Have a written route plan if required by the shipper or by federal/state rules
  • B Avoid weigh stations
  • C Take the most direct route regardless of restrictions
  • D Drive at night only
Correct answer: A
Hazmat routes are often regulated; some loads require an approved written route plan.
Question 12 of 25
Hazardous materials are classified into how many hazard classes?
  • A Five
  • B Nine
  • C Seven
  • D Twelve
Correct answer: B
There are nine hazard classes, from explosives (Class 1) to miscellaneous dangerous goods (Class 9).
Question 13 of 25
A "safe haven" is:
  • A A weigh station
  • B An area approved by federal, state, or local authorities for parking unattended hazmat vehicles
  • C A motel near the route
  • D Any 24-hour gas station
Correct answer: B
A safe haven is the only place a placarded vehicle can be left unattended for extended periods.
Question 14 of 25
A "compatibility" group is used for:
  • A Class 1 explosives, to determine which can be loaded together
  • B All hazmat materials
  • C Cargo tank vehicles only
  • D Drivers, not cargo
Correct answer: A
Compatibility groups (A through S) are used in classifying explosives.
Question 15 of 25
Hazmat shipping papers must list:
  • A Only the price
  • B A proper shipping name, hazard class, and identification number
  • C Only the shipper's name
  • D Driver's license number
Correct answer: B
The "Basic Description" is shipping name, hazard class, and ID number — and packing group when applicable.
Question 16 of 25
A driver who has a hazmat endorsement must:
  • A Notify the carrier of any incident
  • B All of the above
  • C Renew the TSA assessment periodically
  • D Pass a TSA security threat assessment including fingerprinting
Correct answer: B
Hazmat is the only CDL endorsement that includes a federal background check, with renewal cycles.
Question 17 of 25
Drivers transporting hazardous materials must have:
  • A A Hazmat (H) endorsement on their CDL
  • B A medical card only
  • C No special endorsement
  • D A separate license
Correct answer: A
The H endorsement and a TSA security threat assessment are required for placarded hazmat.
Question 18 of 25
A placarded vehicle in motion must always:
  • A Be attended by the driver
  • B Be in a low gear
  • C Have a flashing light on
  • D Be locked
Correct answer: A
The driver must remain with the vehicle except in approved safe havens.
Question 19 of 25
The shipper certification on a hazmat shipping paper means:
  • A The receiver has paid
  • B The shipper guarantees the load is properly classified, packaged, marked, labeled, and described per regulations
  • C The driver has training
  • D The carrier has insurance
Correct answer: B
The shipper certifies HMR compliance; the carrier and driver verify and transport.
Question 20 of 25
A load of hazardous materials may not be parked:
  • A Within 300 feet of a tunnel, bridge, or building used by the public, except for short rest stops
  • B On a public street within 5 feet of the road
  • C In a designated truck stop
  • D In any rest area
Correct answer: A
Parking restrictions for placarded vehicles include distances from open flames, residences, schools, hospitals, and other places.
Question 21 of 25
A driver may NOT smoke within how many feet of a placarded vehicle that contains certain flammable cargo?
  • A 10 feet
  • B 25 feet
  • C 100 feet
  • D 50 feet
Correct answer: B
25 feet is the federal minimum distance for smoking around explosives, flammables, and oxidizers.
Question 22 of 25
When refueling a placarded vehicle:
  • A All of the above
  • B No smoking within 25 feet
  • C Engine must be off
  • D The driver must be at the fueling control
Correct answer: A
All three rules apply during refueling of placarded loads.
Question 23 of 25
Hazmat radioactive materials require:
  • A Vehicle escort
  • B No special handling
  • C Special handling, additional documentation, and route planning
  • D Only a special placard at night
Correct answer: C
Class 7 radioactive shipments have unique placards, transport indices, route planning, and reporting requirements.
Question 24 of 25
A bulk packaging is:
  • A A pallet
  • B One that has more than 119 gallons capacity (liquids) or more than 882 lbs (solids)
  • C Any package over 1 lb
  • D Cardboard boxes only
Correct answer: B
Federal definitions specify thresholds for bulk packaging that trigger additional requirements.
Question 25 of 25
Hazardous materials drivers must avoid:
  • A Tunnels marked as prohibited for hazmat
  • B Routes prohibited for hazmat
  • C All of the above
  • D Driving over a railroad-highway grade crossing without stopping (most placarded loads)
Correct answer: C
Most placarded loads must stop at rail crossings, avoid prohibited tunnels, and follow specified route restrictions.

Study tips for the Texas Hazardous Materials exam

The Hazardous Materials portion of the Texas CDL exam is graded out of the bank of questions the Texas Department of Public Safety draws from each year. While the exact bank is not published, every question is sourced from the Hazardous Materials chapter of the Texas CDL handbook, which itself is derived from the FMCSA Model Commercial Driver's License Manual. That means studying our practice tests, reading the corresponding handbook chapter, and re-reading the parts you got wrong is genuinely the most efficient route to a first-time pass.

Most successful applicants follow a simple cycle: take the practice test cold, write down every question you missed, open the matching chapter of the official Texas handbook, re-read the section that contains the right answer, then re-take the practice test 24 to 48 hours later. The 24-hour delay matters — sleep is when your brain commits new information to long-term memory, and CDL knowledge questions reward that kind of consolidated learning rather than cramming.

Pay particular attention to questions that include qualifier words like always, never, only, primary, or most. CDL test writers love to flip the right answer with a single qualifier. When two answer choices look almost identical, pay attention to the verb (is it must, should, or may?) and to any numbers (14 days, 100 air miles, 8 hours, 70/8 split). On endorsement tests in particular, watch for trick framing where a true statement about a different endorsement is offered as the "correct" answer to a question that is actually about Hazardous Materials.

Test-day logistics matter too. Bring photo ID, your Social Security card or birth certificate, your medical examiner's certificate (DOT card), and proof of state residency if you haven't already submitted those documents. The Texas Department of Public Safety will not let you sit for the knowledge exam without your documentation, and most offices charge an additional fee for re-attempts. Arrive early — the wait at most CDL testing offices runs 30 to 60 minutes — and silence your phone before the exam begins.

Finally, keep your General Knowledge fundamentals sharp even when you're focused on the Hazardous Materials exam. Many states administer multiple knowledge tests in a single sitting, and questions on weight definitions (GVWR, GCWR, GAWR), stopping distance, and the pre-trip inspection routine show up across endorsements. If you're unsure on the basics, sit a fresh Texas General Knowledge practice test before scheduling the real exam.

Next steps

Missed more than four questions? Re-read the Hazardous Materials study guide and the matching chapter in the official Texas CDL handbook. Then come back and re-take the test. Once you can score 22 of 25 or higher on three runs in a row, you're in good shape to schedule the real exam at your local Texas Department of Public Safety office.

Already comfortable with this endorsement? Drill another: TX General Knowledge · TX Air Brakes · TX Combination Vehicles · TX Passenger · TX School Bus · TX Tank Vehicle · TX Doubles / Triples

New to the CDL process in Texas? Read How to apply for a CDL in Texas for the document checklist and step-by-step timeline.