What 178.337-10 means in plain language
FMCSR 178.337-10 addresses accident damage protection for MC331 cargo tanks. An MC331 is a specific type of tank vehicle designed to transport pressurized liquids and gases—think propane, anhydrous ammonia, or other compressed commodities. This regulation requires that these tank vehicles be equipped with proper protective devices to minimize the risk of cargo release in the event of an accident or collision.
The regulation focuses on the structural integrity and protective equipment of the tank itself. If your vehicle is involved in an accident or experiences damage that compromises the tank's ability to contain its cargo safely, this violation comes into play. Inspectors look for damage to protective housings, denting or puncturing of the tank shell, and the presence and condition of required protective devices like bumpers, shields, or endorsement markings that certify the tank's safety rating.
What our enforcement data actually shows
Across our 13 million+ roadside inspection records, 178.337-10 remains extremely rare. We've documented only 2 citations all-time for this code, with 0 citations in the last 12 months and 0 in the last 90 days. This ranks 178.337-10 at #2651 of 3,036 FMCSR codes by citation volume—making it one of the least-cited violations in the hazardous materials category.
None of the 2 all-time citations resulted in an out-of-service placement, giving this code a 0.0% OOS rate. For context, the all-FMCSR average OOS rate is 31.4%, so even when 178.337-10 is cited, enforcement almost never removes the vehicle from service immediately. This suggests inspectors typically see it as a correctable defect rather than an imminent safety threat.
Who gets cited most
Our inspection database shows only 2 all-time citations for this code. The carriers cited include Suburban Propane LP (USDOT 214695) with 1 citation and Tulsa Gas & Gear LLC (USDOT 2136386) with 1 citation. The only vehicle make cited was a Chevrolet. Given the extremely small sample size, these figures reflect isolated incidents rather than systemic patterns, and we cannot reliably identify state or fleet-wide trends.
How severe is this compared to similar codes
Hazardous materials violations vary widely in enforcement intensity and severity. Our data shows that general loading and unloading hazmat violations (codes 177.834A-HMC and 177.834(a)) are far more common, with 3,954 and 3,839 citations respectively, and carry OOS rates of 99.2% and 97.9%—meaning nearly all result in immediate out-of-service orders.
Placarding violations also appear frequently: 177.817(a) has 2,274 citations with a 75.1% OOS rate, while 177.817(e) (placard deterioration) has 2,038 citations but only a 5.2% OOS rate. In contrast, 172.602(c)(1), which addresses maintenance and accessibility of emergency response information, has 1,464 citations with a 0.0% OOS rate—matching 178.337-10's OOS profile. The comparison illustrates that tank protection violations are treated less severely than active hazmat loading and unloading or placarding failures.
How to avoid it
Protecting an MC331 tank from damage begins with intentional pre-trip inspection and operational discipline:
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Inspect the tank exterior at every stop. Before departing, walk around your entire vehicle. Look for dents, cracks, punctures, corrosion, or anything that appears bent or out of shape. Pay special attention to the sides and bottom where road debris or contact with loading docks can cause hidden damage.
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Check protective devices and bumpers. Verify that any protective bumpers, guards, or shields required on your specific tank are present, secure, and undamaged. Loose or missing hardware is a red flag.
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Know your tank's certification and endorsements. Your MC331 should display certification markings and DOT endorsements that confirm it meets safety standards. Ensure these are visible and legible. Faded or missing markings can trigger compliance questions.
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Drive defensively and plan your route. Avoid situations where your tank might strike fixed objects, such as low bridges, narrow alleys, or congested loading areas. Know the clearance of your vehicle and the width and height restrictions of your route.
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Document damage immediately. If you do experience a minor collision or impact, report it to your carrier and document it with photos. This creates a record and ensures the damage is assessed before the next inspection.
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Work with your fleet on maintenance schedules. If you drive for a carrier, ensure your tank is included in regular maintenance cycles that include structural inspections. Rust, corrosion, and fatigue cracks develop over time and may not be visible without deliberate inspection.
Because this violation is so rarely cited, it does not suggest a widespread enforcement focus. However, hazardous materials transport demands the highest standards. A single tank failure could result in spills, environmental damage, injury, or worse. Treating every pre-trip inspection as a safety checkpoint—not just a compliance box—is the best defense.