What 178.345-6 means in plain language
FMCSR 178.345-6 governs the structural integrity and securing of hazmat cargo tanks — specifically DOT 406, 407, and 412 specification tanks. These are the cylindrical trailers that carry liquids, gases, and other hazardous materials. The regulation requires that the supports (the frame and attachment points) and the anchoring system (straps, chains, or other fastening devices) meet DOT specifications and be maintained in proper working order.
When an inspector cites you for 178.345-6, they found that either the tank supports are damaged, misaligned, or deteriorating, or that the anchoring hardware is missing, broken, or insufficient to safely contain the load during transport. This is a structural safety issue: improper tank securement can lead to load shift, tank rupture, or spillage of hazardous material.
What our enforcement data actually shows
Our inspection records show 379 total citations for 178.345-6 across 13 million inspections. In the last 12 months, we recorded 62 citations, and in the last 90 days, 17. This code ranks #1010 out of 3,036 FMCSR codes by citation volume — a relatively low-frequency violation.
The out-of-service rate for 178.345-6 is 9.2% (35 out of 379 trucks), significantly lower than the all-FMCSR average of 31.4%. This means that when inspectors find this violation, they usually allow the vehicle to continue (after a citation is issued) rather than pulling it from service. However, that does not mean the violation is minor — it reflects that many support and anchoring issues can be corrected quickly at the roadside or before the next trip.
Who gets cited most
Across the last 180 days, Texas leads with 35 citations and an 11.4% out-of-service rate. North Carolina follows with 1 citation and a 0.0% out-of-service rate. The variation in OOS rates between these states suggests differences in inspector discretion or the severity of defects encountered, though the small number of citations in North Carolina limits that comparison.
Our data shows fleets such as Pilot Travel Centers LLC (USDOT 91805) with 10 all-time citations for this code, Gemini Motor Transport LP (USDOT 913300) with 7, and Servicios Especializados Alanis SA de CV (USDOT 559477) with 7. These carriers operate hazmat tank fleets regularly, which increases their citation exposure for tank-specific regulations.
How severe is this compared to similar codes
178.345-6 sits in a middle-to-lower severity band within the hazardous materials category. Compare it to peer codes:
177.834A-HMC (General loading/unloading of hazmat) has logged 3,954 citations with a 99.2% out-of-service rate — an enforcement environment where nearly every violation results in immediate removal. 177.817(a) (Placarding violation) shows 2,274 citations and a 75.1% OOS rate, also a high-consequence defect. 172.516(c)(6) (Placard damaged, deteriorated, or obscured) has 1,796 citations but only a 1.6% OOS rate, similar to 178.345-6's low removal frequency.
The gap in OOS rates tells a story: tank support and anchoring defects are treated more like maintenance lapses than active loading or placarding failures. Inspectors often issue the citation but allow you to repair and continue, whereas general loading violations trigger immediate out-of-service orders.
How to avoid it
Based on common co-occurring violations we see in our data, here are concrete steps:
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Perform a detailed pre-trip inspection of tank supports. Look for cracks, rust, bent frame rails, or loose welds on the main support structure. Many 178.345-6 citations co-occur with emergency equipment violations, suggesting rushed or incomplete pre-trip walkarounds — slow down and cover the full tank body.
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Check all anchoring hardware before each load. Verify that straps, chains, and fasteners are present, tight, and not corroded or frayed. Tug on them by hand. Missing or damaged anchoring hardware is the most direct trigger for this citation.
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Watch for commonalities on tank-equipped vehicles. Our data shows FRHT (Freightliner) as the most-cited make (57 citations), followed by KW (Kenworth, 37) and PTRB (Peterbilt, 35). If you operate one of these models, allocate extra time to frame and anchor inspection — these popular tanks may accumulate wear faster in service.
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Document repairs. If you find and repair a support or anchoring issue, make a note in your vehicle maintenance log. Repeated citations for the same vehicle suggest that repairs were not completed or were not recorded.
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Report structural damage immediately. If you notice a bent support, loose anchor point, or cracked frame rail during a trip, contact your dispatcher and mechanic. Do not assume it can wait until the next scheduled maintenance. Structural defects can worsen with road vibration and increase hazmat spillage risk.