What 172.328C means in plain language
FSMR 172.328C requires that MC330 and MC331 cargo tanks—the pressurized steel tanks commonly used to transport liquefied gases and other hazardous materials—must be clearly marked with either "QT" (qualified for transport) or "NQT" (not qualified for transport). These markings tell inspectors and emergency responders at a glance whether the tank meets current safety and pressure-testing standards and is legally authorized to move hazardous cargo.
If you're operating an MC330 or MC331 tank and an inspector finds it unmarked with one of these designations, you'll receive a citation. The marking is not optional—it's a baseline compliance requirement that applies every time the tank is in service.
What our enforcement data actually shows
Across 13 million inspections in our database, code 172.328C has generated 10 all-time citations, with 7 issued in the last 12 months and 1 in the last 90 days. This ranks the violation at #2191 out of 3,036 FMCSR codes by citation volume, making it a relatively uncommon finding on the roadside.
None of the 10 citations on record resulted in an out-of-service order—the OOS rate is 0.0%. By comparison, the all-FMCSR average OOS rate is 31.4%, so this violation is almost never treated as an immediate safety-critical defect that pulls a vehicle off the road. However, the lack of an OOS rate does not mean the violation is insignificant; inspectors will still document it, and it will appear on your inspection record.
The frequency of citations has been light and sporadic: 1 citation in July 2025, a spike to 3 in August 2025, then single citations in November 2025, December 2025, and February 2026.
Who gets cited most
Our inspection records show that Texas accounts for 3 citations in the last 180 days, all of which were not placed out of service (0.0% OOS rate in that state). This is the only state with multiple recorded citations for this code in our recent data.
Among carriers, our data shows fleets such as Midstream Transportation Company with 2 all-time citations for this violation. Other carriers including Water Tech Transportation LLC, Wheat Energy Services Inc, Suregrow Agricultural Transportation Inc, Ahrens Brothers Transport Inc, L E B Enterprises Inc, Inter Petroleum LLC, Red River Transport Inc, Specialized International Transport LLC, and others each recorded 1 citation.
How severe is this compared to similar codes
Placarding and marking violations in the hazardous-materials category vary widely in enforcement intensity and severity. Our data shows that general loading and unloading violations—codes 177.834A-HMC and 177.834(a)—are far more frequently cited (3,954 and 3,839 citations respectively) and result in out-of-service orders 99.2% and 97.9% of the time. Broader placarding violations under 177.817(a) generate 2,274 citations with a 75.1% OOS rate.
By contrast, code 172.516(c)(6)—placard damaged, deteriorated, or obscured—has 1,796 citations but only a 1.6% OOS rate, similar to 172.328C's pattern of infrequent issuance and no out-of-service consequences. Code 172.602(c)(1), covering maintenance and accessibility of emergency-response information, shows 1,464 citations with a 0.0% OOS rate, matching 172.328C exactly.
The takeaway: marking and placard defects are far less likely to trigger immediate removal from service than active loading, unloading, or transportation violations.
How to avoid it
Prevention is straightforward and centers on pre-trip compliance:
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Check your tank markings during every pre-trip inspection. Before departing, visually confirm that your MC330 or MC331 tank displays either "QT" or "NQT" in a location clearly visible to inspectors. If the marking is missing, faded, or illegible, do not move the vehicle.
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Know your tank's qualification status. Understand whether your assigned tank is currently qualified for transport (QT) or temporarily out of service pending testing (NQT). Your fleet or dispatcher should provide this information; do not guess.
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Document tank condition. If you find a marking is damaged, worn off, or unclear, report it to your fleet immediately and request replacement or repainting before your next load. Do not assume the marking will be refreshed at the next stop.
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Cross-check with placard requirements. Our inspection records show that code 172.519 (placard does not meet specifications) co-occurs with 172.328C. While you inspect the tank marking, also verify that placards for the cargo are present, legible, and properly affixed.
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Vehicle maintenance logs. Keep records of any tank maintenance, repainting, or re-marking performed on your assigned vehicles, especially if you operate older units (our data includes citations across Kenworth, Peterbilt, Freightliner, Mack, and other major makes). A simple log showing the date and nature of the work can help defend against a citation if the marking degrades unexpectedly during a trip.