What 172.331C means in plain language
When you haul hazardous materials in bulk form—whether liquids, gases, or solids—federal regulations require that those packages carry proper identification numbers. These ID numbers serve as a safety communication tool: they tell emergency responders, other drivers, and inspection officers exactly what hazard they're dealing with, how to handle it safely, and what protective measures are needed in case of an accident or leak.
A citation under 172.331C means an inspector found that your bulk packaging lacked the required ID numbers, or that the numbers present were incomplete, illegible, or incorrect. This isn't about placard visibility or damage—it's specifically about the identification marking on the container itself. The hazardous material inside may have been safely stowed, properly documented, and correctly labeled in other ways, but the bulk package itself didn't carry the ID number that the rules demand.
For drivers, this is a compliance detail that typically belongs to the loading and pre-trip inspection phase. Before you depart with bulk hazmat, you need to verify that the container is marked with the correct ID number for what's inside. If it's not, you should refuse to haul it until the shipper or carrier corrects the marking.
What our enforcement data actually shows
Across our 13 million+ roadside inspection records, 172.331C is rarely cited. Our database shows just 3 all-time citations for this violation, with 2 issued in the last 12 months and 1 in the last 90 days. This places 172.331C at rank #2551 out of 3,036 FMCSR codes by citation volume.
None of the 3 citations resulted in an out-of-service order—all three vehicles were allowed to continue after the citation was issued. That gives this code a 0.0% out-of-service rate. For context, the all-FMCSR average OOS rate is 31.4%, meaning 172.331C enforcement is significantly less likely to result in immediate roadside removal than most other violations.
The low citation count suggests either strong industry compliance with this requirement, or that inspectors rarely encounter it during roadside inspections. Either way, the enforcement risk for a properly prepared driver is very low.
Who gets cited most
Our inspection records over the last 180 days show 172.331C citations concentrated in one state: Illinois, with 2 citations and a 0.0% OOS rate.
Historically, all-time citations show three carriers with one citation each: New Prime Inc (USDOT 3706), ILMO Products Company (USDOT 78802), and Vega Transport LLC (USDOT 1358485). The single-citation count for each reflects how rarely this violation appears in enforcement data; no carrier shows a pattern of repeated citations.
How severe is this compared to similar codes
172.331C sits within the Hazardous Materials category alongside other FMCSR bulk packaging and hazmat transport rules. Our data reveals stark contrasts:
General loading and unloading violations (codes 177.834A-HMC and 177.834(a)) are cited far more frequently—3,954 and 3,839 times respectively—and result in out-of-service orders 99.2% and 97.9% of the time. These are severe, high-enforcement-priority violations.
Placarding violations like 177.817(a) are cited 2,274 times with a 75.1% OOS rate, indicating consistent enforcement and serious consequences.
By contrast, placard deterioration (172.516(c)(6)) and emergency response information maintenance (172.602(c)(1)) are also cited frequently but result in OOS orders only 1.6% and 0.0% of the time respectively—similar to 172.331C's enforcement posture.
The data suggests that ID number marking violations, while real, are treated as correctable deficiencies rather than immediate safety threats warranting roadside removal.
How to avoid it
Before you accept the load:
- Verify that every bulk package you're about to haul carries the correct, complete, and legible ID number for the hazardous material inside. Cross-reference the ID number on the container against the shipping papers and bill of lading.
- If the ID number is missing, faded, illegible, or incorrect, refuse the load and notify the shipper or your carrier's hazmat coordinator. Do not depart with unmarked or mis-marked bulk packages.
- Inspect all four sides of the bulk container if accessible, since ID numbers must be durable and visible.
During your pre-trip inspection:
- Make ID number verification part of your documented pre-trip checklist. Note the ID number(s) on your inspection report.
- Pay special attention to containers made by manufacturers like Freightliner (FRHT) and Wanc (WANC), which our data shows have appeared in citations for this code; these vehicles may be hauling bulk hazmat more frequently, so inspection discipline is higher-value.
- If you notice fading or damage to an ID number during your pre-trip, document it and inform dispatch before you roll.
If you find a co-occurring marking issue:
- Our inspection data shows that missing ID numbers sometimes appear alongside MARPOL marking violations. A single pre-trip walk-around that confirms both the ID number and any required environmental markings will address both potential problems at once.