CDL Hazardous Materials Endorsement Guide: Hazmat Test Prep

The Hazardous Materials (H) endorsement is one of the most valuable endorsements on a CDL — it opens up higher-paying freight opportunities and is required for any driver transporting placarded hazardous materials. This guide walks you through every requirement, every test topic, and every step of the process. Start with our free CDL hazmat practice tests to see where you stand.

The 3 Requirements for a Hazmat Endorsement

Getting the hazmat endorsement is a three-step process. You must complete all three — no shortcuts:

1. ELDT Hazmat Theory Training (federal requirement): Since February 7, 2022, all first-time hazmat applicants must complete ELDT theory training from an FMCSA-registered provider. The course covers 14 topic areas including hazard classification, placarding, shipping papers, emergency response, and security plans. This is theory only — no behind-the-wheel required. You can complete this for free at CDL Study Buddy's free hazmat ELDT course.
2. TSA Background Check (Security Threat Assessment): You must pass a Transportation Security Administration background check. Start the process at the TSA Hazprint website or by calling the Hazprint help desk. The fee is $86.50. Fingerprints are collected at an enrollment center. The assessment typically takes 15–45 days. You must be a U.S. citizen or have lawful permanent resident status.
3. State Hazmat Knowledge Test: After completing ELDT theory and receiving TSA approval, take the hazmat knowledge test at your state DMV. Most states use 20–30 questions. You need 80% to pass. The test fee varies by state, typically $10–$30.

The 9 Hazard Classes You Must Know

Every hazmat question on the test relates to one of the 9 hazard classes defined in Title 49 CFR. You need to know the class number, the name, and examples of materials in each class:

Placarding Rules: When and Where

Placarding is one of the most heavily tested topics on the hazmat exam. The rules depend on which hazmat table your material falls under:

Table 1 (Always Placard)

Materials in Table 1 require placards in any quantity. These are the most dangerous materials — Class 1 (explosives), Class 7 (radioactive), and certain poisonous gases. If you have even a small amount of a Table 1 material, all four sides of the vehicle must be placarded.

Table 2 (Threshold Placard)

Materials in Table 2 require placards only when the aggregate weight of all hazmat on the vehicle is 1,001 lbs or more. Below that threshold, no placards are required (but shipping papers still are). Most common hazmat falls into Table 2.

Placard Placement

• Placards must be on all four sides of the vehicle — front, rear, left, and right
• Must be visible and legible from a distance of 50 feet
• Must be at least 250 mm (9.84 inches) square
• Must be kept clean and free of damage
• On a tank vehicle, placards must be on each side and each end of the tank

Shipping Papers: What They Must Contain

Shipping papers are your documentation of what hazardous materials you're carrying. The test will ask what information must appear on them:

• Proper shipping name of the hazardous material
• Hazard class and division number
• ID number (UN or NA number)
• Packing group (I, II, or III) if applicable
• Total quantity by weight or volume
• Emergency response telephone number — must be monitored 24/7
• Shipper's certification that the material is properly classified

Where to keep shipping papers: Within reach of the driver when in the cab. When the driver is not in the vehicle, papers must be on the driver's seat or in the door pouch. At a accident scene or during inspection, keep them with you — emergency responders need them.

Emergency Response: What to Do at an Accident Scene

The hazmat test includes several questions about emergency procedures. Here's the exact sequence you must follow:

1. Keep people away: Move bystanders at least 100 feet (some materials require more). Use your warning devices.
2. Don't touch the material: Unless you're trained and equipped for spill response, do not attempt cleanup.
3. Call 911 or the emergency response telephone number on your shipping papers. Report what you're carrying.
4. Consult the Emergency Response Guidebook (ERG): The ERG is organized by UN/NA number and tells you evacuation distances and response procedures.
5. Stay upwind and uphill from the spill. Many hazardous materials create toxic or flammable vapors.
6. Prevent smoking and open flames — especially important for flammable materials.

Loading and Unloading Hazmat: Critical Rules

• No smoking within 25 feet of any hazmat loading or unloading operation
• Engine off during loading/unloading of flammable liquids unless the operation requires the engine to run
• Ground the vehicle when loading or unloading flammable liquids to prevent static electricity
• Brakes set, wheels chocked during all loading/unloading operations
• Never carry Class 1 (explosives) or Class 7 (radioactive) materials in a cargo tank with other hazardous materials
• Segregate incompatible materials — certain hazard classes cannot be transported together (e.g., explosives and flammable liquids)
• Attended at all times — hazmat shipments must be attended or parked in a secure area

How to Study for the Hazmat Test

1. Take a free hazmat practice test to identify your weak areas — start here.
2. Complete the free ELDT hazmat theory course at CDL Study Buddy. It covers all 14 required topics and auto-registers your completion with the FMCSA TPR.
3. Read the hazmat section of your state's CDL handbook — access it through our CDL Handbook page.
4. Memorize the 9 hazard classes and their examples.
5. Know the placarding thresholds: Table 1 = any quantity; Table 2 = 1,001 lbs or more.
6. Retake the practice test until you score 90%+ before scheduling your DMV exam.

Frequently Asked Questions