What 172.328(a) means in plain language
When you haul hazardous materials in a cargo tank, the shipper is required to ensure that tank is properly identified with a unique ID number. This identification must be affixed to the tank itself—not just documented on paper or in your manifest.
If a DOT inspector finds that the cargo tank lacks this ID number or the number is missing or improperly applied, the shipper is responsible for the violation. However, because you're the one operating the vehicle at roadside, you may receive the citation. The regulation holds shippers accountable for providing and affixing the ID# before the load leaves their facility.
What our enforcement data actually shows
Across our 13 million+ inspection records, this specific violation is rare. We've recorded 26 all-time citations for 172.328(a), with zero citations in the last 12 months and zero in the last 90 days. This places the code at #1848 out of 3,036 FMCSR violations by citation volume.
When this violation does result in an enforcement action, the consequences are severe: our inspection data shows a 61.5% out-of-service rate. For context, the all-FMCSR average OOS rate is 31.4%, meaning drivers cited for this violation are nearly twice as likely to be placed out of service compared to the typical FMCSR citation.
Of the 26 all-time citations, 16 resulted in out-of-service orders and 10 did not. The high OOS rate reflects the safety-critical nature of hazardous materials identification in the transportation system.
Who gets cited most
Our inspection records show this violation is concentrated in a small number of carriers. The top citation holders include fleets such as Kendrick Oil Co and Texas Transeastern Inc, each with 2 citations all-time. Several other carriers—Woodworth and Sons Inc, Reeder Distributors Inc, Fred Garrison Oil Co, and others—have each received 1 citation. The distribution across carriers is highly dispersed, indicating this is not a systemic problem for any single fleet but rather an infrequent enforcement event industry-wide.
The rarity of citations in the past 12 months suggests either improved compliance or reduced enforcement activity in this specific violation category.
How severe is this compared to similar codes
Hazardous materials violations in the same regulatory category show a wide range of enforcement intensity. For example, general loading and unloading hazmat violations (177.834A-HMC and 177.834(a)) have been cited 3,954 and 3,839 times respectively, with out-of-service rates of 99.2% and 97.9%—far more frequent and more likely to result in immediate removal from service.
Placarding violations (177.817(a)) have been cited 2,274 times with a 75.1% OOS rate. In contrast, 172.328(a) is substantially less common but carries an OOS rate (61.5%) that exceeds codes like 172.502(a)(1)—placarding general requirements at 18.5% OOS rate—suggesting inspectors view identification defects as more critical than some other placard-related issues.
How to avoid it
Since the shipper is responsible for providing and affixing the ID#, your primary defense is verification before you accept the load:
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Conduct a pre-trip hazmat verification. Before leaving the shipper's facility, visually inspect all cargo tanks for the presence of a clearly visible, legible ID number. Do not accept a load if the tank identification is missing, obscured, or partially affixed.
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Document the ID# on your shipping papers. Cross-reference the tank ID# shown on the hazmat manifest or bill of lading with the physical marking on the tank. A mismatch or absence is a red flag—contact the shipper and do not depart.
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Request corrective action from the shipper immediately. If the ID# is missing or improperly affixed, inform the shipper in writing before loading. Do not proceed with a load that doesn't comply; the citation liability and out-of-service risk are not worth the delay.
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Photograph the tank ID# as part of your pre-trip routine. Many carriers now require driver documentation of hazmat tank identification before departure. This protects you by creating a record of compliance at the point of departure.
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Know your carrier's hazmat procedures. If you drive for one of the carriers handling hazmat, your fleet should have a written shipper compliance verification process. Familiarize yourself with it and escalate any shipper non-compliance to your dispatcher or safety manager immediately.