What 178.337-10A means in plain language
FMCSR 178.337-10A addresses the protection of fittings on MC331 cargo tanks. These fittings—connections, valves, gauges, and other protrusions on the tank itself—must be safeguarded against damage during transport and loading operations. The regulation ensures that sensitive connection points remain intact and functional so hazardous materials stay contained and don't leak or escape during transit.
Protecting these fittings isn't just about preventing small dents. A compromised fitting can lead to material loss, environmental contamination, and serious safety hazards for you, other road users, and the public. FMCSA enforces this standard to keep hazmat cargo secure from origin to destination.
What our enforcement data actually shows
Across our 13 million+ inspection records, 178.337-10A is rarely cited. All-time we see 2 citations, with 2 recorded in the last 12 months and 2 in the last 90 days. Our data shows a 0.0% out-of-service rate—neither of the cited vehicles was placed out of service. This stands in stark contrast to the all-FMCSR average OOS rate of 31.4%, making this one of the least-enforcement-heavy codes in the entire federal motor carrier safety regulations.
178.337-10A ranks #2651 of 3,036 FMCSR codes by citation volume, indicating enforcement is extremely uncommon. The rarity of citations does not mean the regulation is unimportant—rather, it suggests most carriers and drivers maintain compliant cargo tank fittings and inspectors encounter violations only occasionally.
Who gets cited most
Our inspection records show Texas accounted for 2 citations over the last 180 days, all with a 0.0% OOS rate. With such minimal enforcement volume nationally, geographic variation is not material. The data reflects our carrier record indicating fleets such as Juan Alberto Aguilera Mendez (USDOT 3640287) with 2 all-time citations, though this represents a very small sample.
How severe is this compared to similar codes
Fitting protection violations sit at the lighter end of the hazmat enforcement spectrum. Our data shows related loading and placarding codes carry far higher citation counts and OOS rates. For example, 177.834A-HMC (general loading/unloading hazmat) has 3,954 citations with a 99.2% OOS rate, and 177.834(a) has 3,839 citations at 97.9% OOS. Even 172.502(a)(1) (placarding general requirements) has 1,820 citations at 18.5% OOS. By comparison, 178.337-10A's 0.0% OOS rate and 2 all-time citations show this is one of the least-cited hazmat-related violations.
How to avoid it
Protecting MC331 fittings requires vigilance during pre-trip inspection and proper handling during loading:
- Walk around your tank before every trip. Look for loose, cracked, or bent fittings, valve stems, gauge glasses, or any protruding hardware. Touch them gently to confirm they are secure and not moving.
- Inspect connection points during loading. When hazmat is being loaded or unloaded, stay alert for impacts to the tank. Many fitting damage claims occur when loaders strike the tank with equipment or when the cargo hose rubs against a fitting under pressure.
- Verify caps and plugs are in place. Unused openings and connections should be capped, plugged, or sealed. Missing caps expose internal fittings to dirt, moisture, and accidental contact.
- Report damage immediately. If you notice a fitting crack, bend, or leak during your route, stop at a safe location and contact your dispatcher. Do not attempt to repair or drive on with compromised fittings—containment is your legal and safety obligation.
- Know your tank configuration. Familiarize yourself with where all fittings are located on your specific MC331 tank so you can spot damage quickly and communicate clearly with mechanics or inspectors.