What 172.326A means in plain language
You received a citation for 172.326A because an inspector found a portable tank on your vehicle that was not properly marked with its shipping name and identification number. This marking requirement exists so that emergency responders, other drivers, and enforcement officials can quickly identify what hazardous material is inside the tank in case of an accident, leak, or emergency.
The regulation requires that portable tanks carrying hazardous materials display the correct shipping name and a four-digit UN identification number. These markings must be legible, in the right location, and meet Department of Transportation standards. If your tank was missing either the shipping name or the ID number—or both were illegible or incorrect—you meet the citation criteria.
This is a marking and identification violation, not a loading or placarding violation. It's specifically about the tank itself being labeled correctly before or during transport.
What our enforcement data actually shows
Across our 13 million inspection records, 172.326A is a relatively uncommon violation. We've recorded 10 citations all-time, with 7 in the last 12 months and 0 in the last 90 days. The code ranks #2191 out of 3,036 FMCSR codes by citation volume.
The out-of-service rate for this violation is 10.0%—meaning 1 vehicle was placed out of service across the 10 citations on record. This is substantially lower than the all-FMCSR average out-of-service rate of 31.4%, suggesting that inspectors typically do not deem this violation severe enough to remove the vehicle from service. However, low enforcement volume means individual citations can vary significantly in how they are treated.
In the last 12 months, citations have appeared sporadically: 2 in April 2025, 1 in May, 2 in September, 1 in October (which resulted in an out-of-service placement), and 1 in November. This is not a violation we see escalating in frequency.
Who gets cited most
Our inspection records show that Texas accounts for the enforcement data available in the last 180 days, with 2 citations and a 50.0% out-of-service rate. Because enforcement volume is very low nationally, state-level patterns are not fully representative of broader risk.
Among carriers in our database, S BROTHERS WASTE SERVICE INC (USDOT 1616210) appears in our records with 2 citations for this code. The remaining citations are distributed across SELECT WATER SOLUTIONS LLC, RDL TRANSPORTATION INC, ZDS TRANSPORT LLC, LUCIO VALENZUELA ZAMORA, DAXIN TRANSPORTATION LLC, DENMAR COMMERCIAL CONSTRUCTION COMPANY, WATER TECH TRANSPORTATION LLC, and BLACKJACK CHEMICAL LOGISTICS LLC, each with 1 citation. These citations do not imply a pattern of non-compliance; rather, they reflect the rare occurrence of this violation in our inspection database.
How severe is this compared to similar codes
Portable tank marking violations sit in the broader hazmat marking and loading category. When we compare 172.326A to related codes, the contrast is striking.
General hazmat loading and unloading violations—codes 177.834A-HMC and 177.834(a)—generate thousands of citations (3,954 and 3,839 respectively) and carry out-of-service rates above 97%. Placarding violations like 177.817(a) produce 2,274 citations with a 75.1% OOS rate. Even placard deterioration (177.817(e)) appears in 2,038 citations, though with a much lower 5.2% OOS rate.
Your citation, by contrast, reflects a specific and less frequently encountered marking deficiency. The 10.0% OOS rate suggests inspectors view it as correctable documentation or identification oversight rather than an imminent safety hazard. That said, hazmat compliance is non-negotiable; a citation on your record still carries weight in audits and compliance reviews.
How to avoid it
To prevent a 172.326A citation in the future, focus on portable tank inspection and labeling before every load:
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Verify tank markings before loading. Walk around the portable tank and confirm the shipping name is clearly visible and matches your shipping papers. Check that the four-digit UN number is present, legible, and correct. If any marking is faded, damaged, or missing, notify your dispatcher and do not accept the load until it is corrected.
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Check both sides and the top. Markings may be required on multiple surfaces depending on tank orientation and DOT requirements. Don't assume one side is enough; inspect the full perimeter.
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Confirm match with documentation. Cross-reference the tank markings against your bill of lading and hazmat shipping papers before departure. A mismatch is an immediate red flag.
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Know your vehicle. Our data shows Kenworth vehicles (KW) appear most frequently in portable tank citations. Regardless of make, familiarize yourself with where markings should appear on tanks you regularly haul, and include that check in your pre-trip walk-around.
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Report defects to your carrier. If you discover a marking problem during pre-trip, document it and report it immediately. Proceeding with incorrect or missing markings puts you at legal and safety risk.
Hazmat compliance is a shared responsibility between driver and carrier. A clear, honest pre-trip inspection is your best defense against citations and, more importantly, against contributing to an incident.