What 172.301B means in plain language
FMCSR 172.301B addresses a specific hazmat compliance requirement: packages, freight containers, or transport vehicles must be marked with the hazardous materials markings that regulations require. When an inspector cites you for 172.301B, they found that the markings on your cargo—or the container holding it, or the vehicle itself—were either missing or defective in a way that violates the standard.
This is different from a placard violation. Placards are the large diamond-shaped signs that go on vehicle surfaces. Markings under 172.301B are the labels, stencils, or other identifiers that go on individual packages or freight containers to communicate what hazard is inside. If a box of chemicals is sitting on your trailer without a required label, or if a label is so faded or damaged that it's illegible, that's a 172.301B violation.
The regulation applies to anyone shipping hazmat—whether you're a carrier, shipper, or driver. Your responsibility as a driver includes checking that the cargo you accept for transport actually bears the markings required before it leaves the dock.
What our enforcement data actually shows
Across our 13 million+ roadside inspection records, 172.301B is rarely cited. We see 4 citations all-time, with 3 in the last 12 months and none in the last 90 days. This code ranks #2480 of 3,036 FMCSR codes by citation volume—making it one of the least-enforced hazmat-related citations in our database.
The out-of-service rate for 172.301B is 0.0%. None of the 4 citations resulted in a vehicle being placed out of service. This stands in sharp contrast to the all-FMCSR average OOS rate of 31.4%, showing that inspectors treat this violation as a documentation or marking issue rather than an immediate safety hazard requiring vehicle removal.
Over the past 12 months, citations have been sporadic: one in May 2025, one in September 2025, and one in January 2026. This irregular pattern suggests that enforcement depends heavily on the specific load being inspected and inspector diligence during hazmat-focused inspections.
Who gets cited most
Our data shows 1 citation in Texas over the last 180 days, with a 0.0% OOS rate. Because we have very few total citations nationally, state-level variation is limited. Texas is the only state appearing in our recent enforcement records for this code.
All-time, our records show individual citations at carriers such as ACME TRUCK LINE INC (1 citation), DUPUY OXYGEN AND SUPPLY CO INC (1 citation), ENDURA PRODUCTS CORP (1 citation), and PRO JECT CHEMICALS LLC (1 citation). The small citation count means this violation is not concentrated in any particular carrier segment—it appears randomly across different operators and fleet sizes.
How severe is this compared to similar codes
172.301B sits at the lower end of hazmat enforcement severity. Comparing peer codes in the Hazardous Materials category reveals a stark difference:
High-enforcement, high-OOS codes:
- 177.834A-HMC (General loading/unloading hazmat) has 3,954 citations and a 99.2% OOS rate
- 177.834(a) (General loading/unloading hazmat) has 3,839 citations and a 97.9% OOS rate
- 177.817(a) (Placarding violation) has 2,274 citations and a 75.1% OOS rate
Lower-enforcement, lower-OOS codes:
- 172.516(c)(6) (Placard damaged, deteriorated, or obscured) has 1,796 citations and a 1.6% OOS rate
- 172.602(c)(1) (Maintenance/accessibility of Emergency Response information) has 1,464 citations and a 0.0% OOS rate
172.301B's 0.0% OOS rate aligns it with the least-severe marking and information-access violations. Inspectors clearly distinguish between defective markings on packages and more serious hazmat transport breaches like improper loading or placarding that trigger immediate vehicle removal.
How to avoid it
Preventing a 172.301B citation requires diligence before you pick up hazmat cargo and during your pre-trip inspection:
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Inspect cargo labels and markings before accepting the load. Before the shipper seals your trailer, walk it and verify that every package or container bearing hazardous material has the required label or marking visible, intact, and legible. Don't assume the shipper got it right.
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Check for faded, smudged, or damaged markings. Markings degrade during transport, especially on long hauls or in adverse weather. If you notice a label is hard to read, report it to dispatch and document the condition in writing. Some carriers have you re-mark or re-label before departure.
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Know what you're carrying. Review your bill of lading and hazmat paperwork before loading. Understand whether your cargo requires markings under 49 CFR 172.300 series. If paperwork says "hazmat" but you don't see markings, that's your red flag to stop and clarify with the shipper.
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Perform a post-load walk-around. After cargo is loaded and before you seal the trailer, walk the length of it and visually confirm markings are in place. This takes 10 minutes and can prevent a citation.
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Report and document deficiencies immediately. If you discover missing or defective markings after accepting a load, photograph the cargo, note the date and time, and notify your dispatcher or safety manager at once. Don't proceed with a load you know is non-compliant.
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Store marking supplies on your vehicle. If your carrier authorizes it, carry replacement hazmat labels so you can fix minor defects (faded printing, small damage) before an inspector sees them. Check your carrier's policy first.
The low enforcement frequency for 172.301B suggests inspectors spot these violations only when doing detailed hazmat audits or when a shipment is obviously non-compliant. That doesn't mean you should ignore it—hazmat marking requirements exist so emergency responders can identify what's on your vehicle in a crash or spill. A citation may not land you out of service, but it counts against your CSA record and can affect your carrier's safety profile.