What 172.322B-HMM means in plain language
When you transport certain hazardous materials classified as marine pollutants in bulk packaging, the Department of Transportation requires you to apply a specific marking to that package. This marking alerts anyone who handles, inspects, or responds to an incident involving that cargo that the material poses a risk to marine environments if it enters waterways or coastal areas.
The marine pollutant mark is distinct from standard hazard labels and placards. It's a square symbol rotated 45 degrees (a diamond shape) with the words "MARINE POLLUTANT" printed inside. This marking must be clearly visible and applied to bulk packages—typically drums, tanks, or other large containers—before the vehicle leaves the shipper's facility.
If your citation references this code, an inspector found a bulk package on your vehicle that contained a material designated as a marine pollutant but lacked this required marking. The violation occurs whether the marking was never applied, was applied incorrectly, or was obscured or damaged to the point of being unreadable.
What our enforcement data actually shows
Across our 13 million+ roadside inspection records, this code appears remarkably infrequently. We have recorded only 1 citation for 172.322B-HMM in our entire database. In the last 12 months, there have been 0 citations, and in the last 90 days, 0 citations.
This citation ranked #2796 of 3,036 FMCSR codes by enforcement volume, placing it in the lowest tier of violation frequency. The one vehicle cited was not placed out of service, resulting in a 0.0% out-of-service rate for this code. By contrast, the all-FMCSR average out-of-service rate stands at 31.4%, meaning this violation is almost never treated as an immediate safety threat warranting vehicle immobilization.
The rarity of enforcement for this specific code does not mean it is unimportant—it may reflect either strong compliance across the industry or limited inspector exposure to marine pollutant shipments in certain regions. Regardless, if you received this citation, you are among an extremely small group of drivers flagged for this particular marking requirement.
Who gets cited most
Given the extremely limited citation history in our database, geographic and carrier patterns are minimal. Our records show one citation attributed to Schneider National Carriers Inc. (USDOT 264184). The vehicles involved were a CIMC and an International unit.
Without a sufficient dataset spanning multiple states or carriers, we cannot reliably identify which jurisdictions or fleets are disproportionately affected by this enforcement action. If you operate in a region with heavy marine transport or international trade corridors, you may face higher inspector vigilance around marine pollutant markings, but our 13 million inspections do not yet show concentrated citation patterns.
How severe is this compared to similar codes
This code sits within the hazardous materials category, alongside several related marking and placarding violations. A direct comparison illustrates how lightly enforced this specific requirement is:
- 177.834A-HMC (General loading/unloading hazmat) has 3,954 citations with a 99.2% out-of-service rate—indicating severe enforcement and immediate removal from service in almost all cases.
- 172.502(a)(1) (Placarding general requirements) has 1,820 citations with an 18.5% out-of-service rate—a moderate enforcement level that sometimes, but not always, leads to vehicle impoundment.
- 172.516(c)(6) (Placard damaged, deteriorated, or obscured) has 1,796 citations with only a 1.6% out-of-service rate—suggesting inspectors cite the violation but rarely deem it critical enough to halt operations.
Your code, with 1 citation and 0.0% OOS rate, represents an even lower enforcement priority than damaged placard violations. This does not mean non-compliance is acceptable; it means the violation you received is treated as a documentation or marking issue rather than an immediate operational hazard.
How to avoid it
To prevent future citations for missing or illegible marine pollutant markings:
- Verify the hazmat classification before loading. Request the shipping papers and hazmat manifest from the shipper. Confirm whether each bulk package material is listed as a marine pollutant by the EPA or DOT. Do not assume based on the product name alone.
- Inspect all bulk package markings during pre-trip. Walk around each tank, drum, or container and visually confirm the presence of a square-diamond-shaped marine pollutant mark with legible text. Check that the marking is not faded, covered by tape, or obscured by dust or condensation.
- Document what you see. Take a photo of marked packages and retain shipping papers in your cab. If an inspector questions marking compliance, you have contemporaneous evidence of what was loaded and what markings were present.
- Communicate with your dispatcher or safety team if markings are missing or unclear. Do not leave the shipper's facility with bulk packages that lack required markings. A five-minute conversation with dispatch to return to the dock for a corrected load is infinitely preferable to a roadside citation.
- Know your cargo type. Certain chemicals, pesticides, and petroleum products are commonly designated marine pollutants. If you regularly haul these materials, familiarize yourself with the marine pollutant list in 49 CFR Part 172, Appendix B, so you can spot-check markings without relying solely on shipper compliance.