What 172.301A2-HMMS means in plain language
FMCSR 172.301A2-HMMS covers hazardous materials packages that lack proper markings or have defective markings. This applies to individual packages, freight containers, or entire transport vehicles. When you carry hazmat, every package, container, and vehicle involved in that shipment must display the required hazmat markings so that anyone handling, transporting, or inspecting the load can immediately identify what's inside and respond appropriately in an emergency.
Defective markings mean the label is faded, torn, obscured, missing entirely, or applied incorrectly. Even a partially illegible marking can trigger this violation. The regulation exists because proper markings are critical to safety—they alert responders to chemical hazards, guide safe handling procedures, and prevent dangerous mixing or mishandling during load transfers.
What our enforcement data actually shows
Across our 13 million+ inspection records, 172.301A2-HMMS has been cited only 3 times in our all-time database. In the last 12 months, there have been 0 citations, and in the last 90 days, 0 citations. This code ranks #2551 out of 3,036 FMCSR codes by citation volume, making it extremely rare in roadside enforcement.
None of the 3 all-time citations resulted in an out-of-service order—the OOS rate is 0.0%. For context, the all-FMCSR average OOS rate is 31.4%, so 172.301A2-HMMS violations are significantly less likely to result in immediate vehicle removal than most other codes. This does not mean the violation is minor; it reflects enforcement patterns in the field rather than regulatory severity.
Who gets cited most
Our data shows that TIME DISPATCH SERVICES AGENT GROUP INC (USDOT 2061692) received all 3 all-time citations for this code. With so few total citations nationally, state-level breakdowns are not meaningful in this case. Vehicle makes cited include Strick containers (2 citations), Volvo tractors (2 citations), Freightliner (1 citation), and Hyundai trailers (1 citation), though the sample size is too small to identify a pattern.
How severe is this compared to similar codes
Other hazmat-related marking and placarding violations show far higher enforcement volume. For example, 177.834A-HMC (general loading/unloading hazmat) has 3,954 citations with a 99.2% OOS rate, and 177.817(a) (placarding violation) has 2,274 citations with a 75.1% OOS rate. Even 172.516(c)(6) (placard damaged, deteriorated, or obscured), which is similar in scope, has 1,796 citations. In contrast, 172.301A2-HMMS at 3 all-time citations is dramatically less frequent in roadside inspections, suggesting either very strong compliance or limited inspector focus on this specific violation type.
How to avoid it
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Verify package markings before loading. Before any hazmat shipment enters your vehicle, visually inspect every package and container for legible, intact hazmat labels. Do not load anything with faded, missing, or obscured markings.
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Check vehicle placard condition during pre-trip. Walk around your tractor and trailer before departure. Ensure all four placards are clearly visible, not covered by dirt, ice, rain, or cargo, and not damaged or peeling.
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Protect markings during transport. Secure your load so packages don't shift and cover or damage labels. If you stop during a trip and notice a marking has become obscured or damaged, correct it before moving again.
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Document your pre-trip inspection. Record that you checked marking condition as part of your vehicle inspection report. This creates a record that you made a reasonable effort to comply.
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Know your carrier's hazmat procedures. Ask your dispatcher or safety manager about your company's marking verification process. If they have a pre-load checklist for hazmat shipments, use it every time.
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Report defective shipments immediately. If you receive a load where markings are already defective or become damaged before you depart, notify your dispatcher and refuse to transport it until corrected. This protects you and prevents violations.