Hazardous Materials Practice Test 2026: The Ultimate Study Guide

The Hazardous Materials (H) endorsement allows you to haul explosives, gases, flammable liquids, and other dangerous goods. Because the risks are higher, the exam is significantly harder than the General Knowledge test.

To pass, you must understand four key areas: Containment, Communication, Loading, and Driving Rules. This guide breaks them down, followed by a hazardous materials practice test to check your knowledge.

Part 1: The "Communication" Rules

Communication is how you tell the world what you are hauling. This is done through Shipping Papers, Markings, Labels, and Placards.

• Shipping Papers: Must be within reach (in the door pouch) or on the driver's seat when you leave the cab. They must be on top of other papers.
• Placards: Diamond-shaped signs placed on the outside of the vehicle. You must have 4 placards (front, rear, left, right).
• Labels: These go on the packages themselves (boxes, drums), not the truck.

Part 2: Loading & Segregation

You cannot load certain hazardous materials together. This is called "Segregation".

• Cyanides cannot be loaded with Acids (creates deadly gas).
• Explosives cannot be loaded with Primers or Detonators.
• Class 8 Corrosives cannot be loaded above or next to foodstuffs (unless double-contained).

Part 3: Specific Driving Rules

HazMat drivers must follow stricter rules than regular CDL drivers:

• Parking: Never park within 5 feet of the road or 300 feet of a bridge/fire/building if hauling explosives.
• Smoking: No smoking within 25 feet of the truck if hauling flammables, explosives, or oxidizers.
• Tire Checks: You must check your tires every time you stop, or every 2 hours / 100 miles.
• Railroad Crossings: You must STOP 15-50 feet before the tracks. Look and listen. Never shift gears on the tracks.