CDL Hazmat Endorsement Study Guide 2026

Getting the hazmat endorsement

You need a hazmat endorsement to drive any vehicle that must display hazmat placards. The knowledge test has 30 questions in many states, such as Washington and Illinois, and you need 80% (24 correct) to pass.

• For a first hazmat endorsement, finish entry-level driver training with a registered provider before the hazmat knowledge test.
• You must pass a TSA security threat assessment (a background check with fingerprints) for the original endorsement and at each renewal.
• You must pass the hazmat knowledge test again when you renew the endorsement.
• A commercial learner's permit (CLP) holder may never drive a vehicle carrying hazardous materials.
• A first conviction for a major offense such as DUI while hauling placarded hazmat brings a 3-year disqualification.
• Hazmat employees, including drivers, must be retrained at least every three years.

Who does what

The nine hazard classes

Every hazardous material belongs to one of nine hazard classes. Some classes are split into divisions, such as 2.1 or 5.2.

Shipping papers

Shipping papers describe the hazardous materials in a load. Emergency responders depend on them, so they must be correct and easy to find.

• When ordinary items and hazmat are on the same paper, the hazmat must be listed first, highlighted in a contrasting color, or marked with an X in the HM column.
• RQ means reportable quantity: a spill of that amount or more must be reported.
• Hazardous waste must have the word WASTE before its shipping name.
• The papers must give a 24-hour emergency response phone number and emergency response information covering health hazards, fire risks, spill handling and first aid.
• Pages of a multi-page paper are numbered, for example "Page 1 of 4".

Where to keep the papers

Placards

Placards warn others of the hazard from a distance. A placarded vehicle must have placards on each side and each end, at least four in all, readable from all four directions.

Table 1: placard any amount

Table 2: placard at 1,001 pounds or more

For Table 2 materials in non-bulk packages, you do not need placards if the total weight (including packaging) is less than 1,001 pounds. This exception never applies to bulk packaging or to Table 1 materials.

• A DANGEROUS placard may be used instead of separate placards when you carry two or more Table 2 categories. But if you load 2,205 pounds (1,000 kg) or more of one category at one place, you must show that category's own placard.
• With several Class 1 divisions, show only the placard for the lowest division number.
• A NON-FLAMMABLE GAS placard is not needed if you are placarded for flammable gas or oxygen.

Loading and unloading

• Set the parking brake before loading or unloading. Do not use hooks or tools that can damage packages.
• No smoking within 25 feet of explosives, oxidizers or flammables.
• Turn off the engine when loading or unloading explosives or flammable liquids, unless it is needed to run a pump.
• Do not accept or transport leaking packages.
• Cargo heaters are generally not allowed with explosives, flammable liquids or flammable gases.
• Explosives, flammable solids and oxidizers must ride in a closed cargo space. No overhanging or tailgate loads.
• For explosives, use a floor lining with no steel or iron, keep packages away from sharp points, and never drop, throw or roll them. Division 1.1 or 1.2 explosives may not be carried in a triples combination.
• The total transport index of radioactive packages on one vehicle may not be more than 50.
• Never carry POISON-labeled packages in the cab or sleeper, or with food.
• Load glass carboys of corrosives upright, one at a time. Never load nitric acid above other products. Keep cyanides away from acids.
• Check the segregation table: an X means two materials may not be loaded together.

Driving and parking with hazmat

• When fueling, the engine must be off and someone must control the nozzle.
• An overheated tire must be removed and placed a safe distance from the vehicle. A flat tire may be driven only to the nearest safe place for repair.
• Do not use burning flares or fusees near flammable cargo. Use reflective triangles or red electric lights.
• Avoid heavily populated areas, crowds, tunnels and narrow streets unless there is no practical route.
• For Division 1.1, 1.2 or 1.3 explosives, the carrier gives you a written route plan, a copy of the rules and emergency instructions, and you sign for them.
• If you haul chlorine, carry an approved gas mask and an emergency leak kit.

Emergencies

Firefighters and police use the Emergency Response Guidebook (ERG), which is indexed by shipping name and ID number. Your job at a hazmat emergency is to keep people away, warn others, call for help, and give responders the shipping papers.

• Keep people far away and upwind of the scene.
• Never touch or smell leaking material to find out what it is.
• Do not fight a hazmat fire unless you are trained and equipped. Feel trailer doors for heat before opening them, and never open hot doors.
• After a crash, if it is safe to unload explosives, put them at least 200 feet from vehicles and occupied buildings.
• After a radioactive leak, do not use the vehicle until it has been cleaned and checked with a survey meter.