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Bulk packaging: cargo tanks, portable tanks, marking and tank loading

Hazardous Materials (H)4 minManual section 9.5, 9.8

Bulk hazmat moves in big containers, so a mistake can release thousands of gallons. This lesson covers the kinds of tanks, the ID number markings, who must watch loading, and the rules for flammable liquids and compressed gas.

Bulk packaging and types of tanks

Bulk packaging has no inner containers and has: a capacity greater than 119 gallons (450 L) for a liquid; a net mass greater than 882 lb (400 kg) or capacity greater than 119 gallons for a solid; or a water capacity greater than 1,000 lb (454 kg) for a gas. Anything smaller is non-bulk packaging.

  • Cargo tanks are bulk containers built onto the truck (or never taken off for filling and emptying). You fill and empty them right on the truck.
  • Portable tanks are bulk packaging not permanently attached. The product is loaded or unloaded while the tank is off the vehicle; then the tank is put on a vehicle for transport.

You will most often see MC306 tanks hauling liquids and MC331 tanks hauling gases.

Intermediate bulk containers (IBCs) are rigid or flexible portable packages made for mechanical handling. They are bulk packages but do not need the owner's name or shipping name.

Useful terms: a freight container is a reusable container of 64 cubic feet or more; outage or ullage is how much a package falls short of being liquid full, usually in percent; the consignee is the business or person a shipment is delivered to.

Marking bulk packages

You must display the ID number of the hazmat on portable tanks, cargo tanks and other bulk packaging (a dump truck is one example). The number comes from the table's Column 4.

Use black digits 100 mm (3.9 in) high, shown on orange panels, on the placards, or, when no placard is needed, on a white diamond.

Specification cargo tanks also carry markings showing their re-test date.

A portable tank also needs the owner's or lessee's name, plus the contents' shipping name on two opposite sides. The letters must be at least 2 inches tall on tanks over 1,000 gallons and 1 inch tall on tanks under 1,000 gallons.

For a portable tank or other bulk package of 1,000 gallons or more, show the ID number on all four sides (both sides and both ends); under 1,000 gallons, two opposite sides are enough.

Once the portable tank is loaded on the truck, the numbers must still be seen; if they are hidden, put the ID number on all four sides of the truck itself.

Watching tank loading and unloading

The person in charge of loading or unloading a cargo tank must make sure a qualified person is always watching. That person must:

  • be alert,
  • have a clear view of the cargo tank,
  • be within 25 feet of the tank,
  • know the hazards of the materials,
  • know the emergency procedures,
  • be authorized and able to move the cargo tank.

There are special attendance rules for cargo tanks carrying propane and anhydrous ammonia.

Every manhole and valve must be shut before a hazmat tank moves, no matter how small the amount or how short the distance. Moving a cargo tank with any valve or cover open is against the law unless the tank counts as empty under 49 CFR 173.29.

Flammable liquids and compressed gas

Flammable liquids: shut the engine off for loading and unloading. Run it only if needed to operate a pump. When filling through an open fill hole, attach the ground first: connect it before the hole is opened and leave it connected until the hole is shut. Grounding carries away static electricity that could spark a fire.

Compressed gas: the liquid discharge valves stay shut except while product is going in or out. Shut the engine off during loading and unloading unless it drives the transfer pump. If it does, stop the engine once the transfer is done and before disconnecting the hose.

Disconnect every loading and unloading line before you hook up, drop or move a cargo tank. When a trailer or semi-trailer is separated from the tractor, always chock it so it cannot roll.

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: 9.5, 9.8

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. What are cargo tanks?
    1. Small drums on pallets
    2. Bulk packaging permanently attached to a vehicle
    3. Fuel tanks for the engine
    4. Rail tank cars
    Show answer
    Bulk packaging permanently attached to a vehicle

    A cargo tank is bulk packaging built onto the truck; it is filled and emptied on the truck.

  2. What makes a portable tank different from a cargo tank?
    1. It is always smaller than 119 gallons
    2. It carries only gas
    3. It has no valves
    4. It is not permanently attached and is loaded/unloaded off the vehicle
    Show answer
    It is not permanently attached and is loaded/unloaded off the vehicle

    Portable tanks are loaded or unloaded off the vehicle, then put on the vehicle for transport.

  3. The most common cargo tank for liquids is the:
    1. MC306
    2. MC331
    3. DOT 106A
    4. MC338
    Show answer
    MC306

    MC306 is common for liquids; MC331 for gases.

  4. The MC331 cargo tank is commonly used for:
    1. Milk
    2. Dry bulk
    3. Gases
    4. Gasoline
    Show answer
    Gases

    MC331 tanks are the common type for gases.

  5. Identification numbers on bulk packaging are shown in black numbers how tall?
    1. 2 inches
    2. 100 mm (3.9 inches)
    3. 250 mm (9.84 inches)
    4. 1 inch
    Show answer
    100 mm (3.9 inches)

    Black digits 100 mm (3.9 in) high, on orange panels, placards or a white diamond.

  6. Which bulk vehicle must display the ID number of the hazmat it carries?
    1. Only cargo tanks
    2. Only portable tanks
    3. Only rail cars
    4. Cargo tanks, portable tanks and other bulk units, dump trucks included
    Show answer
    Cargo tanks, portable tanks and other bulk units, dump trucks included

    ID numbers go on cargo tanks, portable tanks and other bulk packaging like dump trucks.

  7. A portable tank holds over 1,000 gallons. How tall must the shipping-name letters be, at minimum?
    1. 2 inches tall
    2. 1 inch tall
    3. 3.9 inches tall
    4. 6 inches tall
    Show answer
    2 inches tall

    2 inches for over 1,000 gallons; 1 inch for under 1,000 gallons.

  8. A portable tank that holds 1,000 gallons or more must show the ID number on:
    1. The front only
    2. Two opposing sides
    3. Each side and each end
    4. The top
    Show answer
    Each side and each end

    1,000 gallons or more: each side and each end; less: two opposing sides.

  9. If a portable tank's ID numbers cannot be seen when it is on the vehicle, you must:
    1. Drive anyway
    2. Put the ID number on all four sides of the truck
    3. Remove the tank
    4. Use a DANGEROUS placard
    Show answer
    Put the ID number on all four sides of the truck

    Display the ID number on both sides and ends of the vehicle.

  10. Which bulk packages are NOT required to show the owner's name or shipping name?
    1. Cargo tanks
    2. Portable tanks
    3. Dump trucks
    4. Intermediate bulk containers (IBCs)
    Show answer
    Intermediate bulk containers (IBCs)

    IBCs are bulk packages but do not need the owner's name or shipping name.

  11. The qualified person watching a cargo tank being loaded must be within how many feet of the tank?
    1. 10 feet
    2. 50 feet
    3. 25 feet
    4. 100 feet
    Show answer
    25 feet

    The watcher must be within 25 feet, alert, with a clear view.

  12. Which is NOT a requirement for the person watching cargo tank loading?
    1. Holding a Class A CDL
    2. Being alert with a clear view of the tank
    3. Knowing the hazards and emergency procedures
    4. Being authorized and able to move the tank
    Show answer
    Holding a Class A CDL

    The rules list alertness, clear view, 25 ft, hazard and emergency knowledge, and ability to move the tank; not a specific license class.

  13. Before moving a tank of hazmat a short distance with only a small amount in it, you must:
    1. Leave the valves open to vent
    2. Open the manhole to check
    3. Nothing special
    4. Close all manholes and valves
    Show answer
    Close all manholes and valves

    Close all manholes and valves no matter how small the amount or how short the distance.

  14. When filling a cargo tank of flammable liquid through an open filling hole, you should ground the tank:
    1. After filling
    2. Before opening the filling hole, and keep it grounded until after closing it
    3. Only in dry weather
    4. Only if the engine is running
    Show answer
    Before opening the filling hole, and keep it grounded until after closing it

    Connect the ground before the hole opens and leave it on until the hole is shut.

  15. When loading or unloading flammable liquids, the engine should be:
    1. Running at high idle
    2. Running in gear
    3. Off, unless needed to run a pump
    4. Off only at night
    Show answer
    Off, unless needed to run a pump

    Turn the engine off unless it is needed to operate a pump.

  16. Your engine runs a pump to deliver compressed gas. When should you turn it off?
    1. After product transfer, before unhooking the hose
    2. After unhooking the hose
    3. Before starting the transfer
    4. Only after leaving the site
    Show answer
    After product transfer, before unhooking the hose

    Turn the engine off after transfer and before unhooking the hose.

  17. Liquid discharge valves on a compressed gas tank should be:
    1. Open during travel
    2. Removed after delivery
    3. Half open at all times
    4. Closed except when loading and unloading
    Show answer
    Closed except when loading and unloading

    Keep liquid discharge valves closed except during loading and unloading.

  18. Before coupling, uncoupling or moving a cargo tank, you must:
    1. Open the vents
    2. Unhook all loading and unloading connections
    3. Remove the placards
    4. Start the pump
    Show answer
    Unhook all loading and unloading connections

    Unhook all loading/unloading connections first; also chock uncoupled trailers.