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These 10 free CDL-H questions are organized by exam domain, so you can see how each part of the CDL Hazardous Materials (H) Endorsement Knowledge Test blueprint is tested. Reveal the answer and explanation under each question.
A driver parks a placarded truck and leaves the cab to check in at the receiver's office. Where must the hazardous-materials shipping paper be left while the driver is away from the controls?
Correct answer: B - In the driver's-door holder or on the driver's seat.
At one pickup, a van receives non-bulk packages containing 480 lb of Class 3 material plus 60 lb of packaging, and 520 lb of Class 8 material plus 60 lb of packaging. It also carries 1,800 lb of nonhazardous freight. Both hazardous loads are fully regulated Table 2 materials with no subsidiary hazards. Which calculation and placarding conclusion are correct?
Correct answer: D - 1,120 lb; DANGEROUS may replace FLAMMABLE and CORROSIVE placards.
An otherwise authorized, nonexclusive-use shipment consists of one 28-lb Class 7 package. Its transport index is 0.7, and its maximum surface radiation level is 75 mrem/h. There is no other hazardous cargo. The required package label and vehicle placarding are:
Correct answer: D - RADIOACTIVE YELLOW-III label; RADIOACTIVE placards.
A Packing Group III liquid is in sealed inner bottles inside an otherwise compliant fiberboard box. The UN performance marking includes '4G/Y30/S,' and the completed package weighs 28 kg gross. A loader objects that Packing Group III requires a Z-marked box. Is that objection correct?
Correct answer: A - No; Y includes Packing Group III, and 28 kg is within the 30-kg gross-mass rating.
For open-hole loading of a Class 3 liquid into a cargo tank, select the required sequence for the bond wire connecting the loading rack to the tank shell.
Correct answer: A - Connect before opening any filling hole; disconnect after closing the last filling hole.
The highway segregation table shows an 'O' between the Class 3 flammable liquids and Division 5.1 oxidizers assigned to a van. The packages have no subsidiary hazards, and all other loading requirements are satisfied. What does the 'O' mean for this load?
Correct answer: B - Joint loading is permitted with separation that prevents leakage from the packages from mixing.
A coach carrying paying passengers is offered an 18-lb cylinder of Division 2.3 poisonous gas for delivery to a remote town. No other practicable transportation is available. The shipper proposes securing it in an exterior baggage compartment. Which rule controls acceptance?
Correct answer: D - The cylinder is prohibited because poisonous gas may not be carried on a bus transporting passengers.
During gravity unloading of gasoline, the delivery hose splits. The trained driver is upwind beside an operable remote emergency shutoff, clear of the spill. Operating it will close the tank's internal discharge valve. Which action takes priority?
Correct answer: A - Activate the remote emergency shutoff.
A propane cargo tank is exposed to an external fire, and its pressure-relief valve is venting steadily. A bystander says, 'The valve is working, so the tank cannot explode.' Which assessment correctly addresses that claim?
Correct answer: C - It is incorrect; fire can weaken the tank wall until it fails despite pressure relief.
The truck's engine was legally used to power a gasoline-delivery pump. Later, with gasoline residue still in the cargo tank, the driver pulls up to a diesel dispenser to fuel the truck. Which fueling arrangement is permitted?
Correct answer: C - Engine stopped, with a person in control at the fill point.
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