What 172.324 means in plain language
FMCSR 172.324 requires that non-bulk hazardous substances be properly marked. In practice, this means any hazardous material that doesn't meet the definition of a bulk container must have clear, legible marking that identifies what it is and its hazard class.
Non-bulk packaging includes smaller containers, boxes, cases, or drums that are individual units rather than large tanks or cargo tanks. If you're transporting hazardous materials in these smaller packages, the marking must be visible and readable so that anyone handling or inspecting the load knows what they're dealing with.
This is foundational to the hazmat system: marking tells shippers, handlers, emergency responders, and inspectors what's in each package. Without it, there's no way to know if someone is handling a flammable liquid, corrosive, oxidizer, or other dangerous goods correctly.
What our enforcement data actually shows
Across our 13 million+ inspection records, 172.324 has generated 11 all-time citations, with 5 citations in the last 12 months and 3 in the last 90 days. None of the 11 citations resulted in an out-of-service violation—the OOS rate for this code is 0.0%.
That 0.0% OOS rate is dramatically lower than the all-FMCSR average of 31.4%, meaning this violation is almost never treated as severe enough to pull a vehicle off the road immediately. However, the enforcement volume is very low: 172.324 ranks #2167 out of 3,036 FMCSR codes by citation count. The rarity of citations doesn't mean the requirement doesn't matter—it suggests that most carriers are already marking non-bulk hazmat correctly, or that inspectors are catching other hazmat violations more frequently.
The three citations in the last 90 days appeared in February, March, and July 2025, showing no concentration in any particular season.
Who gets cited most
Over the last 180 days, Texas led with 3 citations, followed by Illinois with 1 citation. Both states had 0.0% OOS rates. The enforcement volume is too low to identify meaningful state patterns, but Texas's concentration reflects its scale as a freight hub and the sheer number of hazmat shipments moving through the state.
Our data shows that across all-time citations, no single carrier has accumulated multiple 172.324 violations. Each of the ten carriers with recorded citations has exactly one: SAIA MOTOR FREIGHT LINE LLC, IOWA CIVIL CONTRACTING INC, XPO LOGISTICS FREIGHT INC, ROTO-ROOTER SERVICES COMPANY, HOOSIERLAND EXCAVATING LLC, REDLINE COURIER EXPRESS INC, XPRESS INTERNACIONAL S DE RL DE CV, HL MOTOR GROUP INC, BAROCK INC, and JR SITE CONSTRUCTION CORP. This distribution suggests the violation is random across carrier operations rather than systemic.
How severe is this compared to similar codes
Within the hazardous materials category, 172.324 sits in the middle of the enforcement spectrum but at the very low end of severity.
General loading and unloading violations (177.834A-HMC and 177.834(a)) dominate by volume—3,954 and 3,839 citations respectively—and come with 99.2% and 97.9% OOS rates. These are treated as critical safety violations. Placarding violations (177.817(a)) have generated 2,274 citations with a 75.1% OOS rate, also quite severe.
By contrast, placard deterioration (177.817(e)) has 2,038 citations with only a 5.2% OOS rate—similar to 172.324 in that inspectors rarely ground vehicles for it. Damaged placard violations are more common than marking violations, but they're also treated leniently.
The closest peer is 172.516(c)(6), which covers placard damage, deterioration, or obscuring. That code has 1,796 citations with a 1.6% OOS rate—even lower than 172.324's 0.0% rate. Both codes focus on the visibility or integrity of hazmat communication, not the movement of dangerous goods themselves, which is why neither triggers out-of-service action.
How to avoid it
The co-occurring violations in recent inspections reveal the pattern: when 172.324 is cited, it typically appears alongside other hazmat documentation and communication failures. Specifically, our data shows it co-occurs with hazmat shipping papers missing or inadequate (172.200A), incomplete hazmat description (172.202B), improper radioactive material labeling (172.403G), and placard issues (172.516C5, 177.817E).
This tells us that marking failures usually happen in the context of broader hazmat compliance gaps—not just a single oversight.
Here's what to do before you accept a hazmat load:
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Verify marking on every package. Before loading, confirm that each non-bulk container has the required hazmat class diamond, proper identification, and any required technical names or additional markings. Check that markings are legible and not worn, faded, or obscured.
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Match marking to shipping papers. Cross-reference the marking on the package against the hazmat shipping papers you're carrying. If the description or hazard class doesn't match, reject the load or ask the shipper to correct it before you leave.
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Inspect placard condition alongside marking. The co-occurring placard violations suggest that when marking problems exist, placard problems are nearby. During pre-trip, verify both the cargo marking and the vehicle placards are visible, not damaged, and correctly affixed.
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Use a pre-trip checklist specific to hazmat. If you're regularly hauling hazardous materials, create or use a checklist that walks you through packaging, marking, placarding, and documentation in sequence. This prevents you from missing one element because you focused on another.
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Know what counts as non-bulk. Non-bulk is anything that isn't a bulk container. If you're moving cases, boxes, drums, or smaller cylinders—anything packaged as individual units—the marking rule applies. Bulk containers have their own separate rules but still need proper identification.
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Ask the shipper to mark it right. You are not responsible for applying marking, but you are responsible for not accepting a load that isn't marked. Before you sign the bill of lading, ask the shipper to show you that marking is complete and correct on the actual cargo.
The low OOS rate for 172.324 means this is a correctable citation, not an immediate safety removal. But hazmat violations cluster: if an inspector finds one, they're likely looking harder at everything else. Getting marking right from the start prevents this violation and makes the other hazmat checks cleaner as well.