What 172.328(c) means in plain language
Cargo tanks used to transport hazardous materials must be clearly labeled to show whether they are "qualified" (QT) or "not qualified" (NQT) for certain types of cargo. This requirement applies specifically to MC330 and MC331 cargo tanks—the most common types used in hazmat transportation.
The markings tell inspectors, shippers, and other drivers what kinds of hazardous liquids the tank is approved to carry. A tank marked "QT" meets all design and safety requirements for the intended cargo; "NQT" means the tank does not meet those requirements and cannot be used for that particular hazmat load. When these markings are absent, there is no way to verify that the tank is safe and legal for its load.
This is a straightforward compliance issue: your tank must have one of these two markings clearly visible. If it doesn't, you cannot legally transport hazardous materials in that tank, and you will be cited at roadside.
What our enforcement data actually shows
Across our 13 million+ inspection records, this citation is extremely rare. We have recorded just 18 all-time citations for 172.328(c), with zero citations in the last 12 months and zero in the last 90 days. This code ranks 1988th out of 3,036 FMCSR codes by citation volume.
None of the 18 citations on record resulted in an out-of-service order—the OOS rate is 0.0%. This is dramatically lower than the all-FMCSR average OOS rate of 31.4%, which reflects the fact that inspectors typically view this as a correctable labeling deficiency rather than an immediate safety hazard that requires removing the vehicle from service.
The rarity of this citation suggests that most fleets and drivers maintain proper cargo tank markings. If you have received this citation, you are part of a very small group, and the fix is straightforward: ensure your MC330 or MC331 tank is permanently and legibly marked with either "QT" or "NQT" before your next load.
Who gets cited most
Our inspection records do not provide a state-by-state breakdown for this code due to its low volume. However, our data shows that across all-time citations, carriers including PLANTA EMBOTELLADORA CRESPOS GAS INC have received 2 citations for this violation, while several other carriers have each received 1 citation. The vehicles cited have included a mix of manufacturers, with FRHT and Freightliner among the makes represented.
The absence of repeat citations at any single carrier or state suggests that this is an isolated compliance gap rather than a systemic fleet issue. When it does occur, it is typically caught and corrected quickly.
How severe is this compared to similar codes
In the Hazardous Materials category, other marking and placarding violations are cited far more frequently. For example, placarding violations under 177.817(a) have generated 2,274 citations with a 75.1% OOS rate, and general loading/unloading violations under 177.834(a) have produced 3,839 citations with a 97.9% OOS rate. By contrast, 172.328(c) has only 18 all-time citations and a 0.0% OOS rate.
Another similar code, 172.516(c)(6)—which addresses placard damage, deterioration, or obscuring—has 1,796 citations but also a very low 1.6% OOS rate. The low enforcement volume for 172.328(c) relative to these peer codes indicates that cargo tank QT/NQT markings are either maintained well by the industry or inspected less frequently than placards themselves.
How to avoid it
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Before you take on a hazmat load: Walk around your assigned MC330 or MC331 tank and verify that it displays either "QT" or "NQT" in a location clearly visible during normal inspection. The marking should be legible and not faded, chipped, or obscured by dirt or corrosion.
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During pre-trip inspection: Make this check part of your standard cargo tank walkthrough. If the marking is missing or illegible, report it to your dispatcher or maintenance department immediately. Do not accept the load until the marking is present and clear.
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Verify with your fleet or lessor: If you operate leased or borrowed equipment, confirm with the owner or lessor that all cargo tanks in service have current QT or NQT markings. Ask your safety manager whether your company has a tank marking audit schedule.
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Document the marking in your records: Some fleets photograph tank markings during acceptance. This creates a record that the tank was in compliance at the time you took it on, protecting you if a marking becomes obscured during transport.
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Know what load you are carrying: Understand whether your assigned tank is qualified (QT) or not qualified (NQT) for the specific hazmat commodity you are transporting. This alignment ensures the marking reflects the actual cargo and reduces confusion at the dock and during inspection.