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Loading and unloading hazardous materials

Hazardous Materials (H)7 minManual section 9.4

Most hazmat accidents begin with a damaged or badly loaded package. Protect every container, keep fire away, brace the load, and learn which classes need special care and which must not ride together.

General loading rules

  • Protect containers. Do not use tools that might damage containers or packaging. Do not use hooks.
  • Set the parking brake before loading or unloading, and make sure the vehicle will not move.
  • Keep away from heat. Many products become more dangerous when heated.
  • Leaks spell trouble! Do not transport leaking packages. Moving a truck while hazmat is leaking is against the law.
  • Brace containers so they cannot fall, slide or bounce. Be very careful with containers that have valves or fittings. All hazmat packages must be secured during transport.
  • No smoking. Keep fire away and do not let people smoke nearby. Never smoke around Class 1 (explosives), 2.1 (flammable gas), 3 (flammable liquids), 4 (flammable solids) and 5 (oxidizers).
  • Keep every package closed for the whole trip. Moving hazmat from one container to another while en route is never allowed. Emptying a cargo tank is allowed; emptying any other package on the truck is not.
  • Cargo heaters: for Class 1, Class 2.1 and Class 3, the rules usually forbid cargo heaters, including automatic heater/air conditioner units. Do not put these in a heated cargo area unless you have studied every rule that applies.
  • Closed cargo space: you may not have overhang or tailgate loads of Class 1, Class 4 or Class 5. They go in a closed cargo area unless every package resists fire and water or is under a tarp that resists fire and water.

Class 1 explosives

Turn your engine off before loading or unloading explosives. Then check the cargo space:

  • Disable cargo heaters: disconnect heater power and drain heater fuel tanks.
  • Make sure there are no sharp points that could damage cargo: bolts, screws, nails, broken side panels, broken floorboards.
  • For Division 1.1, 1.2 or 1.3, use a floor lining. The floor must have no gaps, and the liner has to be non-metallic or non-ferrous metal (metal with no iron or iron alloys). So a steel liner, even stainless steel, is not allowed.

Handle them gently: no hooks or metal tools; no dropping, tossing or rolling; and keep other freight from hitting them.

Moving 1.1, 1.2 or 1.3 from truck to truck on a public road is allowed only in an emergency. If it must be done, warn traffic with red reflectors, flags or electric lanterns.

Damaged explosive packages must never be hauled. Refuse any package that looks damp or has an oily stain.

Do not carry 1.1 or 1.2 in a vehicle combination if:

  • the combination includes a cargo tank that is marked or placarded, or
  • the other vehicle carries Division 1.1 A (initiating explosives), Class 7 packages labeled Yellow III, Division 2.3 Hazard Zone A or B or Division 6.1 Hazard Zone A, or hazmat in a portable tank on a DOT Spec 106A or 110A tank.

Classes 2, 4, 5, 6 and 8

Class 4 and Class 5: Class 4 solids may burn or even explode when exposed to water, heat or air, and some react by themselves. Both classes must ride fully enclosed inside the truck or under a secure cover. Those that become dangerous when wet must stay dry on the road and while being loaded or unloaded. Materials that can heat or ignite on their own need vehicles with enough ventilation.

Class 8 (corrosives): if loading by hand, set fragile containers in one at a time, upright, never dropped or rolled, on a level floor. Stack carboys only when the bottom layer can safely hold the top layer. Nitric acid never goes on top of other freight. Place charged batteries so they cannot leak, keep them upright, and make sure other cargo cannot fall against them or short circuit them.

Never load corrosive liquids next to or above: 1.4 (Explosives C), 4.1 (flammable solids), 4.3 (dangerous when wet), Class 5 (oxidizers), 2.3 Zone B (poison gas).

Never load corrosive liquids with: 1.1 or 1.2, 1.3, 1.5 (blasting agents), 2.3 Zone A (poison gas), 4.2 (spontaneously combustible), 6.1 PG I Zone A (poison liquids).

Class 2 (compressed gases, including cryogenic liquids): if there are no cylinder racks, the floor must be flat. Cylinders must be held upright, or set in racks fixed to the truck, or packed in boxes that stop them from tipping. A cylinder may lie flat only if its design keeps the relief valve in the gas (vapor) space. Loading and unloading Class 2 in cargo tanks needs special training.

Division 2.3 and 6.1 (poisons): never ship them in containers that are connected to each other. A POISON or POISON INHALATION HAZARD package never rides in the cab or sleeper, or with food for humans or animals.

Class 7 radioactive and mixed loads

Class 7: some packages carry a number called the transport index (TI). The shipper labels them Radioactive II or Radioactive III and prints the TI on the label. Radiation passes through nearby packages, so the rules control how many packages you load together and how close they are to people, animals and unexposed film. The TI tells how much control is needed.

The total transport index of all packages in one vehicle must not exceed 50. The separation table (49 CFR 177.842) gives distances. Examples for people or cargo compartment walls: TI 0.1–1.0 → 1 ft; TI 1.1–5.0 → 2 ft; 5.1–10.0 → 3 ft; 10.1–20.0 → 4 ft; 20.1–30.0 → 5 ft; 30.1–40.0 → 6 ft; 40.1–50.0 → 7 ft. Distances to undeveloped film are larger and grow with time (for example TI 1.1–5.0: 3 ft for up to 2 hours, 11 ft for over 12 hours; TI 40.1–50.0: 9 ft for up to 2 hours, 36 ft for over 12 hours).

Mixed loads – do not load in the same vehicle:

  • 6.1 or 2.3 (POISON or poison inhalation hazard labeled) with animal or human food, unless the poison has an approved overpack. Foodstuffs are anything you swallow; mouthwash, toothpaste and skin creams are not foodstuffs.
  • 2.3 Zone A gas or 6.1 PG I Zone A liquids with: Class 3 flammable liquids, 5.1 oxidizers, 5.2 organic peroxides, Class 8 corrosive liquids, 1.1/1.2/1.3 explosives, 1.5 blasting agents, 2.1 flammable gases, Class 4 flammable solids.
  • Charged storage batteries with Division 1.1.
  • Class 1 detonating primers with any other explosives, unless packed in approved containers.
  • 6.1 cyanides or cyanide mixtures with acids, corrosives or other acidic materials that could release hydrocyanic acid (examples: Cyanides, inorganic, n.o.s.; silver cyanide; sodium cyanide).
  • Nitric acid (Class 8) with other freight, unless the acid sits below or beside, never on top of, that freight.

The Segregation Table for Hazardous Materials in the regulations names other materials that must be kept apart.

Example: you have 100 lb of silver cyanide on board and the shipper offers 100 cartons of battery acid (a corrosive acid). Do not load them together; the acid could release deadly hydrocyanic gas.

References and scope

The topic reference is listed below. Sources support verification; the lesson itself is here. The current content needs technical and language review before public launch.

Manual reference: 9.4

Official CDL handbook · Utah ↗StatesOur editorial approach

Put it into practice

Educational questions with explanations. The answer review also works without the interactive quiz.

Preparing your questions…

Review questions with answers

  1. When loading hazmat, you should not use:
    1. Hand trucks
    2. Wheel chocks
    3. Hooks
    4. Gloves
    Show answer
    Hooks

    Do not use hooks or any tool that might damage containers.

  2. Before loading or unloading hazmat, you should:
    1. Set the parking brake and make sure the vehicle will not move
    2. Leave the engine running in gear
    3. Open all packages to check them
    4. Remove the placards
    Show answer
    Set the parking brake and make sure the vehicle will not move

    Set the parking brake so the vehicle will not move.

  3. Around which classes must you never smoke when loading or unloading?
    1. Classes 6, 7, 8
    2. Class 9 and ORM-D
    3. Classes 2.2 and 8
    4. Classes 1, 2.1, 3, 4 and 5
    Show answer
    Classes 1, 2.1, 3, 4 and 5

    Never smoke around Class 1, 2.1, 3, 4 and 5.

  4. Unless you know every related rule, which three classes stay out of a trailer that has a cargo heater or heater/AC unit?
    1. Classes 6, 7 and 8
    2. Class 1, Division 2.1 and Class 3
    3. Classes 2.2, 5 and 9
    4. Classes 4, 5 and 8
    Show answer
    Class 1, Division 2.1 and Class 3

    Cargo heater rules apply to Class 1, 2.1 and 3.

  5. Class 1, 4 and 5 materials may be carried as an overhang or tailgate load if:
    1. The trip is short
    2. It is daytime
    3. All packages are fire and water resistant or covered with a fire and water resistant tarp
    4. The driver has a helper
    Show answer
    All packages are fire and water resistant or covered with a fire and water resistant tarp

    Otherwise they must go in a closed cargo space.

  6. During the trip, you may transfer hazmat from one package to another if it is leaking.
    1. True
    2. False
    Show answer
    False

    False. Moving hazmat between packages during the trip is never allowed; only a cargo tank may be emptied on the vehicle.

  7. Before loading or unloading explosives you must:
    1. Run the engine to charge the battery
    2. Open the trailer heater
    3. Use metal tools to place packages
    4. Turn the engine off
    Show answer
    Turn the engine off

    The engine must be off while explosives are loaded or unloaded.

  8. Is stainless steel an acceptable floor liner for Division 1.1 or 1.2 explosives?
    1. Yes, it does not rust
    2. No, it must be non-metallic or non-ferrous metal
    3. Yes, any metal is fine
    4. No liner is needed
    Show answer
    No, it must be non-metallic or non-ferrous metal

    Stainless steel contains iron; the liner must be non-metallic or non-ferrous.

  9. You should not accept a package of explosives that:
    1. Has a label
    2. Is heavy
    3. Shows dampness or an oily stain
    4. Is in a box
    Show answer
    Shows dampness or an oily stain

    Never transport damaged explosives or packages showing dampness or oily stains.

  10. If you must transfer Division 1.1 explosives between vehicles on a public road in an emergency, you must:
    1. Put out red reflectors, flags or electric lanterns
    2. Use flares
    3. Do it only at night
    4. Remove the placards first
    Show answer
    Put out red reflectors, flags or electric lanterns

    Warn others with red reflectors, flags or electric lanterns.

  11. You may NOT carry Division 1.1 or 1.2 explosives in a vehicle combination if:
    1. The trailer is longer than 40 ft
    2. The weather is hot
    3. The combination has two axles
    4. The combination includes a marked or placarded cargo tank
    Show answer
    The combination includes a marked or placarded cargo tank

    1.1/1.2 may not ride in a combination with a marked or placarded cargo tank (and certain other materials).

  12. Class 4 and 5 materials that become dangerous when wet must be:
    1. Sprayed with water
    2. Kept dry during loading, unloading and transit
    3. Loaded on an open flatbed
    4. Carried in the cab
    Show answer
    Kept dry during loading, unloading and transit

    Keep them dry in transit and during loading and unloading.

  13. Materials that can heat up or ignite on their own must ride in vehicles that have:
    1. Cargo heaters
    2. Metal floors
    3. Sufficient ventilation
    4. Open tailgates
    Show answer
    Sufficient ventilation

    They need vehicles with sufficient ventilation.

  14. When hand-loading breakable containers of corrosive liquid, you should:
    1. Load them one by one, right side up, on an even floor
    2. Roll them into place
    3. Stack them as high as possible
    4. Load them on their sides
    Show answer
    Load them one by one, right side up, on an even floor

    Load breakable corrosive containers one by one, upright, without dropping or rolling.

  15. Nitric acid may be loaded:
    1. Above any other product
    2. In the cab
    3. With food
    4. Only if it is not loaded above any other material
    Show answer
    Only if it is not loaded above any other material

    Nitric acid never goes on top of other freight.

  16. Corrosive liquids must never be loaded next to or above:
    1. Class 9 materials
    2. Division 4.1 flammable solids
    3. Non-hazardous freight
    4. Empty pallets
    Show answer
    Division 4.1 flammable solids

    Never next to or above 1.4, 4.1, 4.3, Class 5 or 2.3 Zone B.

  17. Compressed gas cylinders may be loaded lying down (horizontal) when:
    1. The trip is under 100 miles
    2. The floor is wet
    3. Their design keeps the relief valve in the vapor space
    4. They are empty
    Show answer
    Their design keeps the relief valve in the vapor space

    Horizontal loading is allowed only if the relief valve is in the vapor space.

  18. A package labeled POISON may never be loaded:
    1. In the cab or sleeper, or next to human or animal food
    2. In a closed van
    3. With non-hazardous freight
    4. On a pallet
    Show answer
    In the cab or sleeper, or next to human or animal food

    Never load POISON or POISON INHALATION HAZARD packages in the cab, sleeper, or with foodstuffs.

  19. Which item is NOT considered a foodstuff under the poison loading rule?
    1. Bread
    2. Bottled juice
    3. Animal feed
    4. Toothpaste
    Show answer
    Toothpaste

    Mouthwash, toothpaste and skin creams are not foodstuffs.

  20. The total transport index of all radioactive packages in a single vehicle must not exceed:
    1. 10
    2. 50
    3. 100
    4. 200
    Show answer
    50

    The total transport index in one vehicle must not exceed 50.

  21. Which hazard class uses transport indexes to control how much can be loaded in one vehicle?
    1. Class 3
    2. Class 8
    3. Class 7 radioactive
    4. Class 9
    Show answer
    Class 7 radioactive

    Class 7 radioactive packages carry a transport index.

  22. A radioactive package with a transport index of 1.1 cannot be left within ___ of people or cargo space walls.
    1. 2 feet
    2. 6 inches
    3. 10 feet
    4. 25 feet
    Show answer
    2 feet

    Per the separation table, a TI of 1.1 needs at least 2 feet from people and cargo walls.

  23. Your radioactive packages have a total transport index of 45. Under the separation table, how far must they be kept from people or cargo compartment partitions?
    1. 2 feet
    2. 5 feet
    3. 7 feet
    4. 10 feet
    Show answer
    7 feet

    For a total TI of 40.1 to 50.0, the minimum distance to people or cargo compartment partitions is 7 feet.

  24. You have 100 lb of dry silver cyanide on board. The shipper offers 100 cartons of battery acid. What should you do?
    1. Load the acid on top
    2. Load them side by side
    3. Load them if the cartons are taped
    4. Do not load them in the same vehicle
    Show answer
    Do not load them in the same vehicle

    Cyanides may not be loaded with acids or corrosives that could release hydrocyanic acid.

  25. Charged storage batteries must not be loaded in the same vehicle with:
    1. Class 9
    2. Division 1.1 explosives
    3. Class 3
    4. Non-hazardous freight
    Show answer
    Division 1.1 explosives

    Charged storage batteries may not be loaded with Division 1.1.

  26. Class 1 detonating primers may be loaded with other explosives only when:
    1. The trip is short
    2. The primers are on top
    3. They are in authorized containers or packages
    4. The trailer is refrigerated
    Show answer
    They are in authorized containers or packages

    Detonating primers are not loaded with other explosives unless packed in approved containers.

  27. Division 2.3 poison gas Zone A may not be loaded in the same vehicle with:
    1. Class 3 flammable liquids
    2. Non-hazardous paper
    3. Empty drums that held water
    4. Office supplies
    Show answer
    Class 3 flammable liquids

    2.3 Zone A / 6.1 PG I Zone A may not ride with 5.1, 3, 8, 5.2, 1.1–1.3, 1.5, 2.1 or Class 4.

  28. Before loading explosives, you check the cargo space. Which of these must you do?
    1. Turn on the cargo heater
    2. Leave the floor bare metal
    3. Install metal hooks
    4. Disable cargo heaters, disconnect their power and drain their fuel tanks
    Show answer
    Disable cargo heaters, disconnect their power and drain their fuel tanks

    Disable cargo heaters by disconnecting power and draining heater fuel.