FMCSR 172.336C: Hazmat ID Number Display Citations

It might—but not necessarily. Across our inspection records, 172.336C citations result in an out-of-service order about 53.8% of the time. That's significantly higher than the all-FMCSR average OOS rate of 31.4%, which means inspectors treat this violation seriously. Whether your specific truck gets placed OOS depends on the inspector's findings during that roadside inspection. Our data shows 7 out-of-service placements versus 6 non-OOS citations on this code all-time.

This violation sits in the middle range for hazmat enforcement severity. The 53.8% OOS rate is meaningful, but well below peer violations like general loading/unloading hazmat (177.834A-HMC at 99.2% OOS) or placarding violations (177.817(a) at 75.1% OOS). However, it's considerably higher than some related placard issues—172.516(c)(6) has only a 1.6% OOS rate. The variation suggests that missing or improperly displayed ID numbers are treated as more critical than cosmetic placard damage, but less severe than fundamental loading or placard absence.

First, photograph the citation and the vehicle's current placard and ID number setup. Review the exact notation on the citation slip—what specifically was not displayed or was improperly displayed per 172.336(c) table requirements. Check your hazmat shipping papers against your placards. If the ID number is missing or obscured, get it painted, stenciled, or affixed immediately before the next inspection. Our data shows this code often appears alongside placard specification issues (172.519) and placard attachment problems (172.516C1)—so inspect the entire placard system, not just the ID number. Document your correction with photos for your records.

A 172.336C citation is recorded under the Hazardous Materials safety BASIC in your FMCSA Profile. It contributes to your CSA percentile ranking, though the exact point weighting depends on whether you were placed out of service. Citations flagged as OOS events carry more weight in violation severity calculations. Our records show this code is ranked #2110 out of 3,036 FMCSR codes by citation volume, so it's relatively uncommon—but when it does appear, the 53.8% OOS rate signals it's being enforced with high consequence. A single citation will be visible for 3 years in your CSA profile.

Over the last 180 days, our inspection data shows Texas leading with 2 citations, both resulting in out-of-service orders (100% OOS rate in that state during that window). The overall enforcement volume remains light—only 4 citations in the last 12 months across the entire country, with 2 in the last 90 days. This means 172.336C is not a high-frequency stop code, but when it does occur, Texas inspectors have been enforcing it at the strictest level.

Yes, you can file a DataQs (Improve Safety Data) challenge with FMCSA if you believe the citation is inaccurate or unjustified. For a 172.336C violation, you'd want to gather evidence showing the ID numbers were actually displayed and properly positioned according to the 172.336(c) table—photos taken at the time, witness statements, or maintenance records proving the placards were compliant. DataQs cases require documented proof, not just your word. File within 90 days of the inspection in your FMCSA Profile. Disputed citations remain on your record pending investigation, but a successful challenge removes them retroactively.

Our monthly trend data over the last 12 months shows sporadic enforcement: one citation each in July 2025, October 2025, February 2026, and March 2026. There's no clear upward or downward trend—this is not a high-volume citation code. With only 4 citations in the past year and 2 in the last 90 days, enforcement remains rare. However, when 172.336C does appear, the 53.8% OOS rate means inspectors are not treating it as a warning; they're treating it as a serious compliance gap in hazmat transport.

ECO TRANSPORTES INTERNACIONALES SA DE CV (USDOT 558117) has the highest citation count for this violation with 4 citations all-time. The next nine carriers—GREENWOOD MOTOR LINES, UNITED PETROLEUM TRANSPORTS, MSP TRANSPORTATION, O2 LOGISTICS, PACIFIC LIQUID CARRIER, FAWADI LOGISTICS, RICARDO MAGNO LEAL BUSTAMANTE, SUNOCO RETAIL, and GLP TRANSIT—each have 1 citation. The concentration at one carrier (ECO TRANSPORTES) suggests either a fleet-wide compliance pattern or repeated driver training gaps. If your carrier appears on this list, check whether your hazmat training and pre-trip inspection procedures are being followed consistently.