What 178.338-11B means in plain language
FMCR 178.338-11B governs the manual shutoff valve on MC338 tank vehicles—the portable, pressurized tankers used to haul certain hazardous materials. This valve is a critical safety component that must be present and functional on these tanks. The regulation ensures that drivers and responders have a reliable way to isolate the tank's contents in an emergency, preventing dangerous material release during transport or after an accident.
The manual shutoff valve serves as your primary emergency control if something goes wrong on the road. It's not optional equipment; it's legally required to be there, properly installed, and in working condition before you haul a load. A citation under this code means an inspector found the valve missing, damaged, defective, or inaccessible when your vehicle was inspected at the roadside.
What our enforcement data actually shows
Across our 13 million+ inspection records, 178.338-11B is extremely rare. We have documented just 1 citation for this violation in our entire database, with 0 citations in the last 12 months and 0 in the last 90 days. This code ranks #2796 out of 3,036 FMCSR codes by citation volume, meaning it sits far below the enforcement radar for most carriers and drivers.
When this violation does occur, the consequences are severe. Our data shows a 100.0% out-of-service rate—meaning the one vehicle cited was placed out of service immediately. This is much higher than the all-FMCSR average OOS rate of 31.4%. The reason is straightforward: a missing or defective manual shutoff valve on an MC338 tank is a direct hazmat safety failure that inspectors cannot overlook, regardless of how common the citation is.
Who gets cited most
With only 1 citation on record, geographic and carrier patterns are not meaningful. Our data shows one instance involving a carrier operating under USDOT 2970808, and the citation was issued on a HEIL or PTRB tank vehicle. The extreme rarity of this violation suggests that most carriers and drivers maintain compliant equipment, or that inspectors rarely encounter non-compliant MC338 tanks during roadside enforcement.
How severe is this compared to similar codes
Hazmat-related violations in the same category show dramatically different enforcement patterns. Our inspection records show that general loading and unloading hazmat violations (177.834A-HMC) generate 3,954 citations with a 99.2% OOS rate, and placarding violations (177.817(a)) account for 2,274 citations with a 75.1% OOS rate. By contrast, 178.338-11B's single citation reflects either exceptional compliance or infrequent inspection of MC338 equipment during roadside stops.
The high OOS rate (100.0%) on this code matches the severity of other critical hazmat equipment violations. Even though citations are rare, when one is issued, the vehicle is taken out of service every time. This is consistent with how inspectors treat hazmat safety defects that pose immediate risks to public safety.
How to avoid it
Pre-trip inspection:
- Visually inspect the manual shutoff valve on your MC338 tank before every load. Verify it is present, not loose, and clearly labeled or marked.
- Operate the valve manually (if safe and appropriate) to confirm it moves freely and isn't frozen or corroded.
- Check that the valve handle or controls are not damaged, bent, or missing.
- Ensure the valve is accessible—not blocked by cargo, tie-downs, or mounting hardware.
Equipment maintenance:
- If your carrier assigns you a specific MC338 tank, report any valve issues to maintenance immediately. Do not accept a tank with a defective or inaccessible shutoff valve.
- After any accident or impact involving the tank, have the valve inspected before resuming service.
- Keep a record of pre-trip inspections. Document the condition of the shutoff valve each time you inspect the vehicle.
During transport:
- Never modify, remove, or tamper with the manual shutoff valve.
- Avoid routes or loading configurations that could damage or conceal the valve.
- If an inspector stops you, be prepared to point out the valve's location and demonstrate (if asked) that it is functional.
The extreme rarity of this citation shows that most hazmat drivers maintain compliant equipment. Staying citation-free is straightforward: ensure the shutoff valve is present, accessible, and in good working order every time you perform a pre-trip walk-around.