What 172.402(a) means in plain language
When you transport hazardous materials, your cargo packaging must display labels that identify the primary hazard. But many chemicals and substances present more than one danger — they might be flammable and toxic, or corrosive and water-reactive. A subsidiary hazard label communicates these secondary risks to first responders and other road users.
FMCSR 172.402(a) requires that if a hazmat package has multiple hazards, you must apply labels for each one. A missing subsidiary hazard label means inspectors found a package that was labeled for its primary danger but lacked a required secondary label. This creates a communication gap: emergency personnel or handlers might see only one hazard class and miss critical information about how to safely manage the material.
What our enforcement data actually shows
Across our 13 million+ inspection records, 172.402(a) citations are exceptionally rare. All-time, we see only 32 citations for this code — ranking it #1775 out of 3,036 FMCSR codes by citation volume. Over the last 12 months, our database shows zero citations, and in the last 90 days, zero citations.
The out-of-service rate for 172.402(a) is 0.0% — meaning none of the 32 drivers cited were placed out of service. This is dramatically lower than the all-FMCSR average OOS rate of 31.4%. The rarity of enforcement and the absence of OOS actions suggest that inspectors encounter this violation very infrequently, and when they do, it typically does not trigger vehicle removal from service.
Who gets cited most
Our inspection records show that 172.402(a) citations are so sparse that no single state dominates the data. The top carriers cited include Imperative Chemical Partners Inc (3 citations) and American Welding & Gas Inc (2 citations), but these numbers reflect the overall scarcity of this violation across the industry rather than a pattern of repeat offenders.
Vehicle makes cited include a mix of Ford (3 citations), and smaller counts across Freightliner, International, Peterbilt, Hino, and others — again, too few cases to establish a meaningful pattern.
How severe is this compared to similar codes
Other hazmat labeling and placarding violations in the same category show far higher enforcement volume. General loading and unloading violations (177.834A-HMC and 177.834(a)) each exceed 3,800 citations with OOS rates of 99.2% and 97.9% respectively. Placarding violations (177.817(a)) account for 2,274 citations with a 75.1% OOS rate. Even a related placard code, 172.502(a)(1) on placarding general requirements, has logged 1,820 citations with an 18.5% OOS rate.
By contrast, 172.402(a) sits at the far lower end of enforcement intensity. The 32 all-time citations and zero recent activity suggest this is either a violation that carriers are routinely complying with, or one that inspectors rarely encounter in roadside checks.
How to avoid it
Before you load:
- Request a hazmat manifest or shipping papers from your shipper that clearly identifies all hazards for each package. Do not load until you can verify every container is labeled for all declared hazards.
- If you see a label on a package and suspect it may have secondary hazards (e.g., a flammable liquid that is also toxic), ask your shipper or the packaging manufacturer to confirm all required labels are present.
- Keep a checklist during loading: for every hazmat package on your manifest, physically inspect and confirm both primary and subsidiary labels are visible and legible.
During your pre-trip:
- Walk the entire cargo area and visually verify labels on all hazmat packages match the hazard class listed in your shipping papers.
- Check that labels are not obscured, damaged, or faded. A faded or partially covered label may be mistaken for a missing subsidiary label.
- If you find any package with incomplete labeling, do not leave the dock. Notify the shipper immediately and do not accept the load until all labels are correct.
On the road:
- Regularly inspect your cargo during rest stops. Rough road conditions or shifting freight can dislodge or obscure labels.
- If a label becomes damaged or falls off during transit, you must stop and replace it or notify your dispatcher for guidance. Do not continue with an unlabeled hazmat package.
The extreme rarity of this violation (zero citations in the last year) indicates that most carriers handle subsidiary labeling correctly. Staying diligent during the loading and pre-trip phases will keep you compliant.