FMCSR 172.326C1: Portable Tank ID Marking — Q&A

Not automatically, but it happens 50% of the time. Across our 13 million inspection records, 172.326C1 has been placed out of service in 4 out of 8 all-time citations, giving it a 50.0% OOS rate. This is notably higher than the FMCSA average across all codes (31.4%), meaning inspectors are more likely to ground your vehicle for this violation than for a typical citation. Whether you get OOS depends on the specific circumstances and the inspector's assessment of the hazmat risk.

First: stop transporting the portable tank until it is properly marked with the required identification number. Check the citation closely—our data shows this violation frequently appears alongside placarding violations (172.504A), missing CDL (383.23A2), and emergency response information issues (172.600C). Second: inspect all placards, emergency response documentation, and vehicle markings before moving. Third: contact your carrier's safety manager or compliance team to confirm the portable tank meets all hazmat marking and documentation requirements. Fourth: request the inspection report from your FMCSA file to understand exactly what marking was missing.

Moderately serious, but less severe than many hazmat offenses. Our records rank 172.326C1 #2269 out of 3,036 FMCSR codes by citation volume—it is rarely cited. However, its 50.0% OOS rate exceeds the all-FMCSR average of 31.4%, signaling enforcement severity. Compare this to peer hazmat codes: general loading/unloading violations (177.834A-HMC) have a 99.2% OOS rate, and placarding violations (177.817A) hit 75.1%. Your citation is in the middle range—not the most serious hazmat violation, but serious enough that inspectors often remove vehicles from service.

Texas dominates the citation history. In the last 180 days, our inspection database shows Texas with 4 citations for 172.326C1, accounting for all recent enforcement we track in that window. The same Texas citations show a 50.0% OOS rate (2 out of 4). This violation is extremely rare nationally—only 8 all-time citations across all states—so if you're operating in Texas with portable tanks, be especially vigilant about ID# markings.

Yes. While our statistics don't specify the exact CSA point weight for 172.326C1, hazardous materials violations are weighted heavily in FMCSA's HM BASIC (Hazardous Materials) category. This citation will count against both you as a driver and your carrier in CSA scoring. The violation also frequently co-occurs with placarding and emergency response information breaches, which compound HM BASIC damage. Review your CSA profile within 30–45 days of citation to monitor the impact and request DataQs review if any facts in the citation are inaccurate.

Yes. The DataQs (Database Quality System) process allows drivers and carriers to contest roadside inspection findings. For 172.326C1, your challenge will likely focus on documentation: Was the ID# marking actually absent? Was it obscured or simply not visible at the moment of inspection? Gather photos, maintenance records, and tank documentation to support your case. Hazmat marking violations are equipment-based findings, so if you can demonstrate the marking was present and properly applied, you have solid grounds for contestation. Submit your challenge within the DataQs window (typically 90 days of inspection).

Urgent. Over the last 90 days, our inspection records show 2 citations for 172.326C1, and in February 2026 both resulted in out-of-service orders. The trend suggests enforcement intensity is increasing. If you have been cited, correct the portable tank marking immediately before your next haul. Do not operate a portable tank without proper ID# markings—you risk another citation, compounded penalties, and potential CSA BASIC damage. Once corrected, get the vehicle re-inspected or certified compliant by your carrier before returning to service.

Both. FMCSA hazmat violations appear in both the driver's CSA record and the carrier's Safety Management Cycle (SMC) profile. Your carrier's HM BASIC score and safety rating are directly affected by citations issued to vehicles they operate, regardless of driver error or carrier policy. If you are an owner-operator, the citation is purely on your record. If you drive for a carrier, report the citation to your safety manager immediately—they need to know so compliance can address fleet-wide marking standards and avoid repeat violations across other drivers and equipment.