What 172.328B means in plain language
When you transport gases in a cargo tank, that tank must display the proper shipping name clearly and legibly. This marking tells emergency responders, other drivers, and inspectors exactly what hazardous gas is inside—critical information in case of accident, leak, or emergency.
The shipping name is not the same as a placard or hazard label. It's the specific commercial name of the substance (for example, "propane," "anhydrous ammonia," or "chlorine") that must be marked directly on the tank or on a label attached to it. If your cargo tank is missing this marking, or the marking is illegible or incorrect, you're in violation of 172.328B.
This applies to any cargo tank—whether permanently mounted, semi-trailer, or portable—that carries a hazardous gas and is subject to FMCSR regulation. The marking must be in English and positioned where it's visible during normal transport and inspection.
What our enforcement data actually shows
Across our database of 13 million+ roadside inspection records, 172.328B is a relatively uncommon citation. We've recorded 8 citations all-time, with 1 citation in the last 12 months and 0 in the last 90 days. In July 2025, we saw 1 citation with no out-of-service placement.
When citations do occur, they rarely result in an out-of-service order. Our data shows a 12.5% out-of-service rate for this code—meaning only 1 out of 8 citations resulted in the vehicle being pulled from service. This is significantly lower than the all-FMCSR average out-of-service rate of 31.4%, suggesting inspectors often issue this as a correctable deficiency rather than an immediate safety threat.
Ranked #2269 of 3,036 FMCSR codes by citation volume, 172.328B sits in the lower-frequency tier. This reflects either strong compliance among tank operators or limited inspection focus in this specific area—likely a combination of both.
Who gets cited most
Our inspection records show that Windstar Trucking LLC (USDOT 2126272) has received 2 citations for this violation—the highest count in our dataset. Other carriers such as Fuel Mark Inc, Gerardo Aguilar Garcia, Quality Tank SA de CV, Getaweldercom Inc, Butch's Propane LLC, and Midstream Transportation Company each appear with 1 citation.
With only 8 total citations across the entire dataset, no single state dominates. However, the violation appears across multiple jurisdictions, indicating it's not isolated to one region or enforcement approach.
How severe is this compared to similar codes
172.328B exists within the Hazardous Materials enforcement category, where marking and placarding violations are common. Our data shows a stark contrast in enforcement severity:
Placarding and loading violations like 177.834A-HMC (General loading/unloading hazmat) appear 3,954 times with a 99.2% out-of-service rate—nearly all result in immediate vehicle removal. Similarly, 177.834(a) shows 3,839 citations with 97.9% OOS rate. General placarding violations (177.817(a)) appear 2,274 times with a 75.1% OOS rate.
More similar marking codes like 172.516(c)(6) (Placard damaged, deteriorated, or obscured) show 1,796 citations but only a 1.6% out-of-service rate. By comparison, 172.328B's 12.5% OOS rate sits between the high-severity loading codes and the low-severity damage/deterioration codes, reflecting that a missing or incorrect shipping name is treated as a moderate-level hazmat marking deficiency.
How to avoid it
Preventing a 172.328B citation starts with your pre-trip inspection routine:
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Verify tank markings before departure: Walk around your cargo tank and confirm the shipping name is present, legible, and matches the bill of lading or shipping papers. Don't rely on memory or assume it's marked from a previous load.
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Check for weathering and visibility: Inspect the marking for fading, dirt, or damage that might make it illegible. Clean the tank if necessary. Markings must be visible from a distance—inspectors will read them from several feet away.
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Confirm correct substance name: Cross-reference the tank marking against your manifest or shipping papers. A placard or hazard label alone is not sufficient; the actual shipping name must be on the tank itself.
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Know your tank's history: If you're assigned a cargo tank regularly, familiarize yourself with where its markings are located. Different tank configurations place shipping names in different spots. For common makes like Freightliner and International units that appear in our citation data, learn the standard marking locations for your equipment.
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Report missing or damaged markings immediately: If you notice a shipping name marking is missing, illegible, or incorrect before you depart, notify your dispatcher or fleet safety manager. Do not attempt to transport the tank until the marking is corrected. This prevents a citation and keeps responders safe.
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Keep shipping papers accessible: While not the same as the tank marking, having clear, updated shipping papers ensures you can quickly confirm the substance identity to any inspector.