What 172.332(c) means in plain language
Hazardous materials regulations require that every placard on a truck display not just the hazard class symbol, but also the specific class or division identification number for that material. This number tells responders and inspectors exactly what type of hazard they're dealing with—for example, the difference between flammable liquid (Class 3) and oxidizer (Class 5).
When you get cited for 172.332(c), it means an inspector found that one or more of your placards was missing this required identification number. The placard itself may have been present and visible, but incomplete. This is a critical detail because first responders and emergency personnel rely on these numbers to know what they're facing in an accident or incident.
What our enforcement data actually shows
Across our database of 13 million+ roadside inspections, 172.332(c) citations are extremely rare. We have recorded only 57 all-time citations for this code, with zero citations in the last 12 months and zero in the last 90 days. This code ranks #1588 out of 3,036 FMCSR codes by citation volume.
When this citation does occur, it is very unlikely to result in an out-of-service order. Our data shows a 1.8% out-of-service rate for 172.332(c)—meaning only 1 vehicle was placed out of service across the 57 citations on record. This is dramatically lower than the all-FMCSR average OOS rate of 31.4%. In practical terms, if you receive this citation, the inspector is documenting a compliance gap but the vehicle is typically permitted to continue operation after the citation is issued.
Who gets cited most
Our inspection records show this citation is so infrequent that no clear state or carrier pattern emerges from the data. The top carrier cited for 172.332(c) is Transportes Arlequin SA de CV (USDOT 1879622) with 3 citations across our entire database. The next carriers each have only 1–2 citations on record. This rarity means that if you have been cited, you are statistically among a very small group of drivers and fleets.
Vehicle makes cited for this violation include Volvo and Freightliner (each with 5 citations), Kenworth (4), and others, but again the absolute numbers are low enough that no equipment-specific pattern is reliable.
How severe is this compared to similar codes
Understanding where 172.332(c) sits in the hazmat compliance universe helps you gauge the seriousness. Our data on peer codes in the Hazardous Materials category shows a dramatic range:
General loading/unloading violations (177.834A-HMC and 177.834(a)) are by far the most frequently cited hazmat codes, with 3,954 and 3,839 citations respectively—and they carry an out-of-service rate near 99%. These violations involve actually moving or handling hazmat improperly and create immediate safety risk.
Placarding violations (177.817(a)) account for 2,274 citations with a 75.1% OOS rate, indicating that when a placard is missing or completely absent, enforcement is much more aggressive.
Placard deterioration (177.817(e)) has 2,038 citations but only a 5.2% OOS rate—similar to 172.332(c)—suggesting that cosmetic or condition issues are treated as documentation problems rather than safety-critical failures.
The rarity and low OOS rate of 172.332(c) suggests inspectors view missing ID numbers as a labeling/documentation issue rather than an active safety threat, especially if the placard itself is present and the vehicle is not in motion with an emergency.
How to avoid it
Because this citation is so uncommon and your opportunity to prevent it is strongest during pre-trip inspection and load verification, focus on these concrete actions:
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Verify every placard before departing. Before accepting a loaded hazmat shipment, walk the truck and confirm that each placard is not only present and affixed correctly, but that the class or division number is legible and complete. Do not rely on the shipper or broker—your eyes, your truck, your responsibility.
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Know the hazmat classes and their ID numbers. Familiarize yourself with the nine hazmat classes and their division breakdowns (e.g., Class 3 = Flammable Liquids, Class 5 = Oxidizers and Organic Peroxides). If you can recognize the number at a glance, you can spot missing ones faster during inspection.
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Inspect placards for wear and fading. Even if the number is printed correctly, sun, weather, and road spray can fade or obscure it. If a placard looks worn or the number is hard to read, report it to your dispatcher and request a replacement placard before you depart.
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Photograph placards before and after loading. Keep a record of what the truck looked like when loaded and at any major fuel or rest stop. If an inspector cites you later, you have evidence of the condition when you accepted the load.
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Confirm shipper compliance before pickup. Ask the shipper to verify that all placards are complete and legible before you hook up. Get acknowledgment in writing if possible. This prevents you from inheriting a compliance failure that was created at the origin.
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Request proper training from your carrier. If your fleet is hauling hazmat, ensure you've completed DOT hazmat endorsement training and that your carrier's safety program includes placard inspection checklists. Familiarize yourself with the specific placards used in the materials your fleet typically transports.