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Hazardous materials rules for all drivers

General Knowledge4 minManual section 2.23

Every commercial driver should know some basics about hazardous materials (hazmat). You must be able to recognize hazardous cargo and know whether you can haul it without a hazardous materials endorsement on your CDL. Hazmat means products that could harm health, safety or property while they are being transported.

The nine hazard classes

  • Class 1 – Explosives: ammunition, dynamite, fireworks.
  • Class 2 – Gases: propane, oxygen, helium.
  • Class 3 – Flammable (liquids): gasoline, acetone.
  • Class 4 – Flammable solids: matches, fuses.
  • Class 5 – Oxidizers: ammonium nitrate, hydrogen peroxide.
  • Class 6 – Poisons: pesticides, arsenic.
  • Class 7 – Radioactive: uranium, plutonium.
  • Class 8 – Corrosives: hydrochloric acid, battery fluid.
  • Class 9 – Miscellaneous hazardous materials: formaldehyde, asbestos.
  • No class number: ORM-D (Other Regulated Material–Domestic), e.g. hair spray or charcoal; and combustible liquids, e.g. fuel oils, lighter fluid.

Why there are rules

The rules have three goals: contain the product, communicate the risk, and ensure safe drivers and equipment.

  • Contain the product: many hazmat products can injure or kill on contact. Rules tell shippers how to package safely, and other rules cover how drivers load, haul and unload bulk tanks. Together these are called containment rules.
  • Communicate the risk: the shipper warns dock workers and drivers with a shipping paper and diamond-shaped hazard labels.

After a crash or spill you may be hurt and unable to explain what you carry. Firefighters and police can reduce damage and injury if they know what hazmat is on board. So you must mark hazmat shipping papers clearly or keep them on top of other papers, and keep them:

  • In a pouch on the driver's door, or
  • In clear view, within reach while driving, or
  • On the driver's seat when you are out of the vehicle.

Placards and identification numbers

Placards are signs on the outside of a vehicle that identify the cargo's hazard class. Every placarded vehicle needs at least 4 identical placards: front, rear and both sides. They must be readable from all four directions.

Each placard measures at least 9.84 inches (250 mm) square and is mounted standing on one point, like a diamond. On cargo tanks and other bulk packaging, the contents' identification number appears on the placards or on orange panels.

Identification numbers are 4-digit codes used by first responders to identify hazmat. One ID number may cover more than one chemical. On shipping papers the number comes after the letters “NA” or “UN”. The U.S. DOT Emergency Response Guidebook (ERG) lists chemicals and their ID numbers.

When you need the hazmat endorsement

Not every vehicle carrying hazmat needs placards (placard rules are in Section 9). A hazmat load that needs no placards is one you may drive. If placards are required, you may not drive it unless your license carries the hazardous materials endorsement (H).

Drivers of placarded vehicles must learn to load and carry hazmat safely, and must pass a written test to get the endorsement.

A tank vehicle endorsement is needed for a CMV built to carry liquid or gas in a tank with an individual capacity of more than 119 gallons and a total (aggregate) capacity of 1,000 gallons or more, permanently or temporarily attached. The liquid or gas does not have to be hazardous.

  • If you do not know whether your vehicle needs placards, ask your employer.
  • Driving a vehicle that needs placards without the endorsement is a crime. You will be cited and not allowed to drive your truck — costing time and money.
  • Not placarding when required risks lives: in a crash, emergency crews will not know about your hazardous cargo.
  • Hazmat drivers must also know which products can and cannot be loaded together (Section 9). Before loading more than one type of product, find out if it is safe. If you do not know, ask your employer and check the regulations.

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: 2.23

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. Hazardous materials are products that:
    1. Pose a risk to health, safety and property during transportation
    2. Are worth more than $10,000
    3. Weigh more than 1,000 pounds
    4. Must be kept frozen
    Show answer
    Pose a risk to health, safety and property during transportation

    By definition, hazmat is any product that could harm health, safety or property while it is being transported.

  2. The three goals of the hazardous materials rules are to contain the product, communicate the risk, and:
    1. Lower shipping costs
    2. Speed up delivery
    3. Protect the cargo from theft
    4. Ensure safe drivers and equipment
    Show answer
    Ensure safe drivers and equipment

    The rules aim to contain the product, communicate the risk, and ensure safe drivers and equipment.

  3. How does the shipper communicate the risk of hazardous materials to dock workers and drivers?
    1. With a phone call
    2. With shipping papers and diamond-shaped hazard labels
    3. With a colored trailer
    4. With a sticker on the windshield
    Show answer
    With shipping papers and diamond-shaped hazard labels

    The shipper warns of the risk with a shipping paper and diamond-shaped hazard labels.

  4. When you leave the vehicle, hazardous materials shipping papers must be:
    1. Locked in the sleeper
    2. Taken with you
    3. On the driver's seat
    4. In the glove box
    Show answer
    On the driver's seat

    Hazmat papers go in a pouch on the driver's door or in plain view within reach while you drive; when you leave the cab, put them on the driver's seat.

  5. Why must hazmat shipping papers be marked or kept on top of other papers?
    1. So emergency responders can find them quickly after a crash
    2. So the dispatcher can sign them
    3. So they do not get wet
    4. Because they are larger
    Show answer
    So emergency responders can find them quickly after a crash

    After a crash you may be unable to speak. Firefighters and police must quickly find the hazmat papers to reduce harm.

  6. A placarded vehicle must display at least how many identical placards?
    1. 1
    2. 2
    3. 3
    4. 4
    Show answer
    4

    At least 4 identical placards: front, rear and both sides, readable from all four directions.

  7. Hazmat placards must be at least what size?
    1. 6 inches square
    2. 9.84 inches (250 mm) square
    3. 12 inches round
    4. 15 inches square
    Show answer
    9.84 inches (250 mm) square

    Placards are at least 9.84 inches (250 mm) square, set on a point in a diamond shape.

  8. Hazmat identification numbers are:
    1. Two letters only
    2. The shipper's phone number
    3. Four-digit codes used by first responders
    4. The trailer's license plate
    Show answer
    Four-digit codes used by first responders

    ID numbers are four-digit codes used by first responders; on shipping papers they follow "UN" or "NA".

  9. On shipping papers, a hazmat identification number is preceded by:
    1. The letters UN or NA
    2. The letters HM or RQ
    3. The letters DOT or ID
    4. The hazard class name
    Show answer
    The letters UN or NA

    The identification number is preceded by the letters NA or UN.

  10. Which book lists hazardous chemicals and their identification numbers?
    1. The FMCSA driver handbook
    2. The state CDL manual
    3. The vehicle owner's manual
    4. The U.S. DOT Emergency Response Guidebook (ERG)
    Show answer
    The U.S. DOT Emergency Response Guidebook (ERG)

    The DOT Emergency Response Guidebook (ERG) lists chemicals and their ID numbers.

  11. Cargo tanks and other bulk packaging show the identification number of their contents on:
    1. The cab door
    2. Placards or orange panels
    3. The mud flaps
    4. The bill of lading only
    Show answer
    Placards or orange panels

    Bulk packaging displays the ID number on placards or orange panels.

  12. You may drive a vehicle carrying hazardous materials without the hazmat endorsement if:
    1. The trip is under 50 miles
    2. The cargo is less than half the trailer
    3. The vehicle does not require placards
    4. Your employer gives permission
    Show answer
    The vehicle does not require placards

    You can drive a hazmat-carrying vehicle that does not need placards. If it needs placards, you must have the endorsement.

  13. Driving a vehicle that needs placards without a hazardous materials endorsement:
    1. Is a crime; you will be cited and not allowed to drive the truck
    2. Is allowed for short local trips
    3. Only results in a warning
    4. Is allowed if the placards are covered
    Show answer
    Is a crime; you will be cited and not allowed to drive the truck

    It is a crime. You will be cited and stopped from driving, costing time and money.

  14. A tank vehicle endorsement is required for a vehicle carrying liquids or gases in tanks with an individual capacity of more than ____ gallons and an aggregate capacity of 1,000 gallons or more.
    1. 50
    2. 250
    3. 1,000
    4. 119
    Show answer
    119

    The tank endorsement applies to tanks over 119 gallons each with a total of 1,000 gallons or more. The liquid need not be hazardous.

  15. Gasoline and acetone belong to which hazard class?
    1. Class 2 – Gases
    2. Class 3 – Flammable
    3. Class 5 – Oxidizers
    4. Class 8 – Corrosives
    Show answer
    Class 3 – Flammable

    Gasoline and acetone are Class 3 flammable liquids.

  16. Battery fluid and hydrochloric acid are examples of:
    1. Poisons
    2. Oxidizers
    3. Corrosives
    4. Explosives
    Show answer
    Corrosives

    Class 8 corrosives include hydrochloric acid and battery fluid.

  17. Propane, oxygen and helium are in which hazard class?
    1. Class 2 – Gases
    2. Class 1 – Explosives
    3. Class 4 – Flammable solids
    4. Class 7 – Radioactive
    Show answer
    Class 2 – Gases

    Class 2 is gases, such as propane, oxygen and helium.

  18. Which hazard class includes pesticides and arsenic?
    1. Class 9
    2. Class 5
    3. Class 3
    4. Class 6 – Poisons
    Show answer
    Class 6 – Poisons

    Class 6 is poisons, such as pesticides and arsenic.

  19. Hazardous materials placards are used to:
    1. Show the weight of the cargo
    2. Warn others of the hazard class of the cargo
    3. Show the driver's endorsements
    4. Advertise the shipper
    Show answer
    Warn others of the hazard class of the cargo

    Placards are signs on the outside of the vehicle that identify the hazard class to warn others.

  20. You plan to load two different hazardous products together and are not sure it is allowed. You should:
    1. Load them on opposite sides of the trailer
    2. Load them if they fit
    3. Ask your employer and check the regulations
    4. Put the heavier one on top
    Show answer
    Ask your employer and check the regulations

    Hazmat drivers must know which products can be loaded together. If unsure, ask your employer and consult the rules.

  21. Hair spray and charcoal are examples of:
    1. ORM-D (Other Regulated Material–Domestic)
    2. Class 1 explosives
    3. Class 7 radioactive
    4. Class 4 flammable solids
    Show answer
    ORM-D (Other Regulated Material–Domestic)

    ORM-D has no class number; examples are hair spray and charcoal.