21 HazMat Endorsement (H) Practice Questions & Answers
Every HazMat Endorsement (H) practice question from the CDL Practice Test, with the correct answer and a short explanation.
Start practice test →1. The federal Hazardous Materials Regulations rest on three basic intents. Which set states them correctly?
- A.Insure the shipment, inspect the packages, and register the carrier with the state.
- B.Tax the shipper, license the package maker, and log every stop along the route.
- C.Contain the product, communicate the risk, and ensure safe drivers and equipment.✓ Answer
- D.Limit the load weight, restrict night travel, and require an escort vehicle along.
The regulations work through three intents: contain the product so it cannot escape its package, communicate the risk through labels, markings, placards and shipping papers, and ensure safe drivers and equipment through licensing, endorsement and inspection rules.
Source: 49 CFR Part 171 (purpose and scope of the HMR); AAMVA Model CDL Manual, Hazardous Materials sectionReport a problem with this question
2. A shipper offers a drum of sulfuric acid, a liquid that burns skin and eats metal. Which hazard class covers it?
- A.Class 6.1, Poisons, the class for materials toxic if swallowed or touched.
- B.Class 5.1, Oxidizers, the class for materials that give off oxygen readily.
- C.Class 4.2, Spontaneously Combustible, for materials that ignite on their own.
- D.Class 8, Corrosives, the class for materials that burn skin or eat metal.✓ Answer
Class 8 is defined by the destructive effect the material has on living tissue and on metal, which is exactly what an acid does; oxidizers, poisons and spontaneously combustible solids are defined by other behaviors and carry different labels and placards.
Source: 49 CFR 173.136 (Class 8 definition); Hazardous Materials Table, 49 CFR 172.101Report a problem with this question
3. Your load includes one small package of a Division 2.3 poison gas and nothing else hazardous. What do the placarding rules require?
- A.Placards are required for any amount, because 2.3 appears in Table 1 of the rules.✓ Answer
- B.Placards are required only if the package is loaded in a tank of any capacity.
- C.Placards are required only once the shipment reaches 1,001 pounds gross weight.
- D.Placards are not required, because a single package falls under a small exception.
Table 1 hazards, which include Division 2.3 poison gas, must be placarded in any quantity; the 1,001-pound aggregate threshold applies only to the Table 2 hazard classes, so a single small package of 2.3 still places placards on all four sides.
Source: 49 CFR 172.504 Table 1Report a problem with this question
4. You carry 600 pounds of a Class 3 flammable liquid and 500 pounds of a Class 8 corrosive, both Table 2 materials, and nothing else. Do you need placards?
- A.Yes, because any quantity of a Class 3 flammable liquid must always be placarded.
- B.No, because no single hazard class by itself reaches the 1,001-pound figure.
- C.Yes, because the combined weight of Table 2 materials is 1,001 pounds or more.✓ Answer
- D.No, because Table 2 materials are placarded only when carried in bulk packages.
For Table 2 hazards the 1,001-pound trigger is read on the total of all Table 2 materials aboard, not class by class, so 600 plus 500 pounds equals 1,100 pounds and placards are required for both classes present.
Source: 49 CFR 172.504(c) (Table 2 aggregate gross weight)Report a problem with this question
5. Your vehicle must be placarded for the load it carries. How many placards go on, and where?
- A.Four identical placards, one on each side and one on each end of the vehicle.✓ Answer
- B.One placard on the driver's side, plus a duplicate kept with the shipping papers.
- C.Two identical placards, one on the front bumper and one on the rear doors.
- D.Three identical placards, one on each side and one on the rear of the vehicle.
A placarded vehicle must show at least four identical placards, one on each side and one on each end, so that anyone approaching from any of the four directions can read the hazard before reaching the vehicle.
Source: 49 CFR 172.504(a)Report a problem with this question
6. When may the DANGEROUS placard be displayed in place of separate class placards?
- A.When two or more Table 2 classes are aboard and the total reaches 1,001 pounds.✓ Answer
- B.When the driver cannot identify the class of one package on the shipping paper.
- C.When any single Table 2 class aboard weighs less than 1,001 pounds in total.
- D.When Table 1 materials are aboard and the shipper has not supplied placards.
The DANGEROUS placard is a convenience for mixed Table 2 loads: two or more Table 2 classes totaling 1,001 pounds or more may be shown with it, but if 2,205 pounds or more of one class is loaded at a single place, that class's own placard must be used.
Source: 49 CFR 172.504(b)Report a problem with this question
7. The shipping paper describes your material as an inhalation hazard. What does that add to the placarding?
- A.The load needs no extra placard, because the class placard already shows the risk.
- B.The load needs a DANGEROUS placard in place of the class placards it would need.
- C.The load needs a RADIOACTIVE placard added, because inhalation risk is rated there.
- D.The load needs an INHALATION HAZARD placard along with the placards already required.✓ Answer
Materials that are poisonous by inhalation are treated as an added communication problem, so the INHALATION HAZARD placard goes on in addition to, never instead of, the placard the hazard class itself calls for.
Source: 49 CFR 172.505(a)Report a problem with this question
8. A shipping paper lists both hazardous and non-hazardous freight. How must the hazardous entries be identified?
- A.Circled in pencil by the driver, or underlined twice, or marked PG in the quantity column.
- B.Listed last, or written in capital letters, or marked with the letter G beside the entry.
- C.Kept on a separate page, or stamped by the carrier, or marked NA in the remarks column.
- D.Listed first, or highlighted in a contrasting color, or marked with an X in the HM column.✓ Answer
On a mixed shipping paper the hazardous entries must stand out by one of three permitted methods, because a responder must be able to find them at a glance without reading every line of ordinary freight.
Source: 49 CFR 172.201(a)(1)Report a problem with this question
9. Where must the shipping papers for a hazardous load be while you drive, and after you step out?
- A.In the sleeper berth while driving, and handed to a dock worker when out of the cab.
- B.In the glove box while driving, and locked inside the trailer once the driver steps out.
- C.In a pouch on the driver's door or in clear reach, and on the driver's seat when out.✓ Answer
- D.In a folder behind the seat while driving, and carried in a pocket when out of the cab.
The rule places the papers where a responder can find them fast even if the driver is hurt: within immediate reach with the seat belt fastened or in the door pouch, and left in plain sight on the seat when the cab is empty.
Source: 49 CFR 177.817(e)Report a problem with this question
10. What must the shipping paper carry so responders can act if the material is released?
- A.The carrier's insurance policy number and the name of the terminal dispatch manager.
- B.Emergency response information and a phone number monitored at all times in transit.✓ Answer
- C.The shipper's business hours and the address of the nearest hospital along the route.
- D.The driver's license class and endorsement codes plus the medical examiner's number.
Emergency response information must accompany the shipping paper and an emergency phone number must be monitored the whole time the shipment moves, so a responder reaching the scene can learn the hazards and reach someone who knows the product.
Source: 49 CFR 172.600 through 172.606 (emergency response information and telephone number)Report a problem with this question
11. The Hazardous Materials Table shows the word Forbidden in a material's entry. What does that mean?
- A.The material may be carried only by a driver holding both the H and N endorsements.
- B.The material may be moved only if the shipper supplies a written route plan first.
- C.The material must never be transported, no matter how it is packaged or labeled.✓ Answer
- D.The material may be moved only in a placarded tank with a built-in extinguisher.
A Forbidden entry is an absolute bar, not a condition to satisfy: the material is too unstable or too dangerous to move by highway at all, and no packaging, routing or endorsement makes the shipment lawful.
Source: 49 CFR 172.101 Hazardous Materials Table, Column 3 entry 'Forbidden'Report a problem with this question
12. Who is responsible for marking and labeling the packages in a hazardous shipment?
- A.The carrier's dispatcher, who labels the packages once the shipping paper is signed.
- B.The receiving facility, which labels packages when the load is checked in at delivery.
- C.The shipper, who marks and labels each package before offering it to the carrier.✓ Answer
- D.The driver, who marks and labels each package after loading it onto the vehicle.
Marking and labeling belong to the shipper because only the shipper knows what is inside the package; the driver's matching duty is to refuse a shipment whose packages are leaking, unmarked or wrongly labeled.
Source: 49 CFR 172.300 and 49 CFR 172.400 (shipper marking and labeling duties)Report a problem with this question
13. What does the loading rule require in the cargo space when Division 1.1 or 1.2 explosives are carried?
- A.A metal deck plate bolted down so that the packages cannot shift during transport.
- B.A floor lining that leaves no exposed steel or iron in contact with the packages.✓ Answer
- C.A rubber mat under each package and a fire blanket draped over the whole load.
- D.A layer of sand at least two inches deep spread across the whole cargo floor.
A spark from steel or iron rubbing against a package is the hazard the rule is written against, so the cargo space must have a floor lining or covering with no exposed ferrous metal where the explosives sit.
Source: 49 CFR 177.835(c) (floors of vehicles carrying Division 1.1 and 1.2 explosives)Report a problem with this question
14. How must packages bearing a poison label be loaded?
- A.Away from food, feed, and other edible cargo, since contamination is the concern.✓ Answer
- B.On top of the other freight, so that any leak drains down and away from them.
- C.Just behind the cab, where the driver can watch them through the rear window.
- D.In the sleeper berth area, where they are shielded from weather and road spray.
The segregation rule exists because a leak that reaches food or animal feed can poison people far from the crash, so poison-labeled packages may not be loaded in the same space with edible products.
Source: 49 CFR 177.841(e) (poisons loaded with foodstuffs)Report a problem with this question
15. Your placarded vehicle is parked on a public roadway. What does the attendance rule require?
- A.Someone in the sleeper berth of the vehicle who can be woken by a passerby.
- B.Someone within 100 feet with a clear view, awake, and able to move the vehicle.✓ Answer
- C.Someone within 300 feet who can reach the vehicle within five minutes if needed.
- D.Someone at the terminal who knows the route and can be reached by telephone.
An attended vehicle means a qualified person is within 100 feet, has an unobstructed view of it, is awake and not in the sleeper berth, and knows the hazards and how to move the vehicle in an emergency.
Source: 49 CFR 397.5(d) (attendance of placarded vehicles)Report a problem with this question
16. A cargo tank that carried a hazardous material has been emptied but not cleaned or purged. At a railroad crossing you must do what?
- A.Stop, because an emptied tank that still holds residue is treated as a loaded one.✓ Answer
- B.Slow down and cross without stopping, because an empty tank carries no hazard.
- C.Cross without stopping once the placards have been turned to their blank side.
- D.Stop only if the crossing has flashing lights or a gate arm across the roadway.
Cargo tank vehicles used for hazardous materials must stop at railroad crossings whether loaded or empty, because residue and vapor left in an uncleaned tank can still burn or explode if a train strikes the vehicle.
Source: 49 CFR 392.10(a)(3) (cargo tanks, loaded or empty, must stop at railroad crossings)Report a problem with this question
17. How often must the driver of a placarded vehicle examine the tires?
- A.Once a week, and any time the tire pressure warning lamp comes on in the cab.
- B.At the start of each trip and each time the vehicle is parked during that trip.✓ Answer
- C.Only at the start of each trip, since roadside checks are the mechanic's job.
- D.Every four hours of driving, and again before the vehicle is fueled anywhere.
An overheated or flat tire is a common ignition source under a placarded load, so the driver must look at the tires before starting out and again at every parking stop, replacing or repairing any tire found overheated or leaking.
Source: 49 CFR 397.17 (tires on placarded vehicles)Report a problem with this question
18. During a stop you find a package on the trailer leaking a hazardous material. What should you do?
- A.Seal the package with tape from the cab, then finish the run as it was scheduled.
- B.Park, secure the area, keep away from the leak, and send someone else for help.✓ Answer
- C.Drive on to the delivery point, where the receiver can handle the cleanup work.
- D.Move the load to a truck stop, then wash the spilled material off the trailer floor.
A leaking package is never repaired by the driver and the vehicle is never driven farther than safety requires: park it, keep people and yourself clear of the material and its vapor, and get qualified help to the scene.
Source: 49 CFR 177.854(a) through (c) (leaking or damaged packages)Report a problem with this question
19. Which situation requires an immediate telephone report to the National Response Center?
- A.A release in which a person is killed, or an injured person must be hospitalized.✓ Answer
- B.A shipping paper that lists the packing group ahead of the identification number.
- C.A placard that blows off the trailer and is replaced at the next fuel stop on route.
- D.A shipment that arrives at the consignee more than four hours behind its schedule.
Immediate telephone notice is reserved for incidents with serious public consequences, such as a death, an injury requiring hospitalization, an evacuation of an hour or more, or closure of a major transportation artery.
Source: 49 CFR 171.15 (immediate notice of certain hazardous materials incidents)Report a problem with this question
20. Before a state may issue a hazardous materials endorsement, what must the applicant do?
- A.Obtain a written letter of clearance from the shipper's safety department.
- B.Complete a road test in a placarded tank vehicle with an examiner aboard.
- C.Register the vehicle with the federal pipeline agency and post a cargo bond.
- D.Submit fingerprints and pass a security threat assessment run by the TSA.✓ Answer
The hazardous materials endorsement is a security credential as well as a knowledge credential, so on top of the written test the applicant is fingerprinted and cleared through a Transportation Security Administration threat assessment.
Source: 49 CFR 383.141; 49 CFR Part 1572 (TSA security threat assessment)Report a problem with this question
21. You are fueling a placarded cargo tank loaded with a flammable liquid. What does the smoking rule require?
- A.Smoking is allowed once the placards are covered and the fuel hose is disconnected.
- B.Smoking is allowed inside the cab with the windows closed and the doors latched.
- C.Nobody may smoke within 10 feet of the vehicle unless the engine has been shut off.
- D.Nobody may smoke within 25 feet of the vehicle while the flammable load is aboard.✓ Answer
The 25-foot no-smoking zone applies around a vehicle carrying explosives, oxidizers or flammable materials, and fueling adds vapor to the air, so no lit cigarette, match or flame may come near the vehicle at all.
Source: 49 CFR 397.13 (smoking near placarded vehicles)Report a problem with this question
Practice questions based on the AAMVA/FMCSA model CDL manual. Requirements vary by state — study your state's official CDL manual before your exam. Official CDL info →