What 172.331A-HMM means in plain language
When you transport hazardous materials in bulk packages, those packages must carry identification numbers that clearly show what's inside. This code specifically addresses situations where one or more bulk packages on your vehicle are missing these required ID numbers. The ID number is a critical part of hazmat marking—it tells emergency responders, inspectors, and other drivers exactly what hazardous substance is in that container.
This isn't about placards on the vehicle itself; it's about markings directly on the bulk package. If an inspector finds a bulk container without the proper identification numbers displayed, they'll cite this violation. It's a paperwork and labeling problem at the package level, not a structural or safety defect in the container itself.
What our enforcement data actually shows
Across our 13 million+ inspection records, 172.331A-HMM is extremely rare. We've recorded only 2 citations all-time, with 2 citations in the last 12 months and 0 in the last 90 days. None of the 2 citations resulted in an out-of-service order, giving this code a 0.0% OOS rate—significantly lower than the all-FMCSR average of 31.4%.
Ranked #2651 of 3,036 FMCSR codes by citation volume, 172.331A-HMM sits near the bottom of enforcement activity. This doesn't mean the requirement is ignored; it means most carriers and drivers get it right. When citations do occur, inspectors typically treat them as a marking deficiency rather than an operational hazard serious enough to pull the vehicle from service.
The 12-month trend shows one citation each in November 2025 and December 2025, with no pattern of escalation or regional surge.
Who gets cited most
Our data shows citations concentrated in two states over the last 180 days: California with 1 citation (0.0% OOS rate) and Oregon with 1 citation (0.0% OOS rate). Both inspections resulted in no out-of-service placement.
When looking at carriers across all records, our data shows fleets such as The Corgiat Corporation (USDOT 2804782) and Tutash Express Inc (USDOT 3487141) each with 1 citation. Neither case led to an out-of-service order. These individual citations don't signal systemic non-compliance; they reflect isolated instances of missing ID numbers on bulk packages.
How severe is this compared to similar codes
In the broader hazardous materials marking and handling category, 172.331A-HMM sits on the lenient end of the enforcement spectrum. Compare these peer codes:
177.834A-HMC (General loading/unloading of hazmat) has 3,954 citations with a 99.2% OOS rate—nearly all inspections result in vehicle removal. 177.817(a) (Placarding violation) shows 2,274 citations with a 75.1% OOS rate. 172.516(c)(6) (Placard damaged, deteriorated, or obscured) has 1,796 citations but only a 1.6% OOS rate, closer to 172.331A-HMM's profile.
What this tells you: missing ID numbers on bulk packages is treated as a labeling/paperwork issue, not a loading or structural hazard. Inspectors rarely halt operations for this violation alone. However, it's usually cited alongside other hazmat defects, which can escalate consequences.
How to avoid it
Before every load:
- Inspect every bulk package visually. Walk around the tank, tote, or container and confirm the ID number is present, legible, and affixed to the exterior. Don't rely on what the shipper said—verify it yourself.
- Know what you're carrying. Cross-reference the shipping documents (bill of lading, hazmat shipping papers) with the ID number on each package. If the numbers don't match, flag it immediately with dispatch or the shipper.
- Check for weather damage. Rain, salt spray, or prolonged sun exposure can fade or obscure ID markings. If you see fading, request reapplication before departure.
- Document the pre-trip. Take a photo or note the presence and legibility of ID numbers on your pre-trip report. This creates a record that you inspected and found compliance at load time.
During transport:
- Avoid covering markings. Don't load cargo, secure straps, or tie-downs over the ID numbers. Keep them fully visible for roadside inspection.
- Report deterioration immediately. If you notice an ID number becoming unreadable during a trip, contact your dispatcher and the shipper for instructions. Don't proceed hoping it won't be inspected.
These steps are straightforward pre-trip tasks that take minutes but prevent a citation and the operational friction that follows.