What Is the X Endorsement on a CDL?

If you've looked closely at a commercial driver's license, you may have noticed a series of letters listed under "endorsements" or "restrictions." Each one signals something specific about what the driver is — or isn't — authorized to do. The X endorsement is one of the more common combinations you'll see on CDLs held by tanker drivers, and understanding what it means requires knowing how CDL endorsements work in general.

How CDL Endorsements Work

A commercial driver's license (CDL) authorizes you to operate large commercial vehicles, but the base license doesn't cover every type of vehicle or cargo. Endorsements are add-ons to a CDL that expand what you're legally permitted to drive or haul. Each endorsement requires additional testing — sometimes written, sometimes skills-based — and must be applied for through your state's licensing authority, typically the DMV or its equivalent.

Common CDL endorsements include:

What the X Endorsement Specifically Means

The X endorsement is not a standalone endorsement with its own unique test. Instead, it's a combination endorsement that represents both the N (tank vehicle) endorsement and the H (hazardous materials) endorsement together.

In plain terms: a driver with an X endorsement is authorized to operate a tank vehicle that carries hazardous materials. Think of fuel tankers, chemical transport trucks, or other large liquid-cargo carriers moving regulated substances on public roads.

When a driver holds both the N and H endorsements separately, some states will automatically display the X code on the license in place of listing both letters individually. In other states, both N and H remain listed alongside each other, and the X may or may not appear. How your state handles this display varies.

What It Takes to Get the X Endorsement 🚛

Because the X endorsement represents two separate qualifications, earning it means satisfying the requirements for both the N and H endorsements:

For the N (Tank Vehicle) Endorsement:

• Pass a written knowledge test covering the handling of liquid and gaseous cargo, surge effects, and tank vehicle inspection
• No separate skills test is federally required for the N endorsement, though some states may have additional requirements

For the H (HazMat) Endorsement:

• Pass a written knowledge test on the safe transportation of hazardous materials, placarding, and emergency response
• Complete a TSA security threat assessment, which includes a federal background check and fingerprinting — this is federally mandated and cannot be waived
• HazMat endorsements must be renewed periodically and the background check repeated

Once both are satisfied and your state issues the combined code, the X appears on your license to show you meet both standards.

Why the X Endorsement Matters to Employers

For carriers that haul fuel, chemicals, or other regulated liquids, the X endorsement is a practical hiring requirement. It signals that the driver has cleared federal background screening, understands the risks of liquid cargo dynamics (including surge and slosh, which can affect braking and handling), and knows how to properly placard and document hazardous loads.

Drivers with the X endorsement often work in:

• Petroleum and fuel delivery
• Chemical transport
• Industrial liquid cargo hauling

Some employers specifically require the X rather than accepting N and H separately, particularly because the combined role is common in their operations.

Factors That Shape the Process

Several variables affect how straightforward — or involved — getting an X endorsement will be:

• Your state's specific testing requirements — written test content and pass scores can differ
• TSA processing time — the federal background check for the H portion can take several weeks and is outside state DMV control
• Existing endorsements — if you already hold N or H, you may only need to add the other and pay the applicable fee
• Renewal timelines — the HazMat portion typically requires renewal every five years, with another background check; the tank endorsement renewal process varies by state
• Any disqualifying history — certain criminal convictions, immigration statuses, or security flags can prevent approval of the HazMat portion regardless of other qualifications

What the X Endorsement Doesn't Cover

Holding an X endorsement doesn't automatically authorize every tanker or hazmat operation. Drivers still need to:

• Hold the appropriate CDL class (A or B) for the vehicle they're operating
• Comply with all DOT and FMCSA regulations governing the specific cargo being transported
• Follow employer-specific requirements and additional state regulations that may apply

Some specialized cargo — radioactive materials, for instance — may carry requirements beyond what the X endorsement alone addresses.

The Pieces That Are Specific to You 🔎

Whether you're working toward an X endorsement or trying to understand what it means on a license you've seen, the full picture depends on your state's CDL testing structure, your current endorsement status, any background check considerations, and the type of carrier operation you're entering. Federal standards create the baseline — but the process, fees, and timelines you'll actually encounter run through your state's licensing authority and the TSA's federal screening system.