Direct answers about 178.338-8 citations, out-of-service risk, and what drivers need to do next. Based on 13M+ inspection records.
Ranks #2,664 of 3,146 FMCSR codes by citation frequency • OOS rate of 0.0% is below the FMCSR-wide average of 33.3%.
MC338 Pressure relief devices
Direct answers grounded in TruckCodex inspection data
No. Across our 13 million inspection records, 178.338-8 citations have never resulted in an out-of-service order. The 0.0% OOS rate for this code contrasts sharply with the 31.4% average OOS rate across all FMCSR violations. Out of 2 all-time citations in our database, both vehicles remained in-service. This code is cited but does not trigger immediate roadside placement out of service.
178.338-8 is significantly less severe than related hazmat violations. While 178.338-8 has a 0.0% OOS rate, peer codes in the Hazardous Materials category show dramatically higher enforcement consequences: placarding violations (177.817(a)) sit at 97.9% OOS rate with 3,839 citations, and general loading/unloading hazmat (177.834A-HMC) reaches 99.2% OOS rate across 3,954 citations. The rarity and zero out-of-service history suggest inspectors view 178.338-8 findings as lower-risk than core hazmat handling violations.
No—178.338-8 is one of the rarest violations in the FMCSR database. Our records show only 2 all-time citations, placing it at rank #2651 out of 3,036 FMCSR codes by citation volume. In the last 90 days, there were zero citations. The two citations on record occurred in June 2025 and September 2025, each involving one carrier. For comparison, the most-cited peer code in hazmat (general loading/unloading) has logged 3,954 citations.
Since 178.338-8 relates to MC338 pressure relief devices on hazmat transport, take these steps: (1) Have a qualified technician inspect the pressure relief device system on your tank vehicle. (2) Document the inspection and any repairs in writing. (3) Review your maintenance logs to confirm when the device was last serviced. (4) Correct the deficiency before operating again with hazardous materials. (5) Keep records of the repair or certification for the citation defense or CSA data quality challenge. Although the code has never triggered an out-of-service order, compliance is required for safe hazmat transport.
Yes. If you believe the citation is factually incorrect—for example, if the inspector misidentified equipment or misread a maintenance date—you can file a FMCSA DataQs (Data Quality and Improvements) request within the established timeframe. DataQs is the formal process for drivers and carriers to dispute specific violations in the CSA database. Document the evidence (photos, maintenance records, inspection reports) that contradicts the finding. Given that 178.338-8 is equipment-based, providing calibration certificates or service records is your strongest defense. Success depends on demonstrating the violation either did not occur or was misclassified.
Our database shows two carriers cited for 178.338-8: TEAMONE LOGISTICS LLC (USDOT 2525242) with 1 citation, and CRYOGENICS FREIGHT LLC (USDOT 3916810) with 1 citation. Both citations are part of the 2-citation total across our 13 million inspection records. The involvement of cryogenics freight suggests 178.338-8 is relevant to carriers operating cryogenic or pressurized hazmat tanks, though the extremely low volume means this code affects very few operations.
Urgent—but not because of immediate out-of-service risk. Although the 0.0% OOS rate means you won't be stopped mid-trip, a pressure relief device defect on an MC338 tank is a safety-critical issue. Hazmat regulations require functional relief systems to prevent overpressurization and potential accidents. The rarity of this citation (0 in the last 90 days, only 2 all-time) indicates inspectors prioritize other violations, but that doesn't reduce the equipment risk. Correct the deficiency before the next hazmat load. Operating with a faulty relief device violates federal hazmat safety requirements and increases accident liability.
Our records show four vehicle makes cited in the two 178.338-8 cases: FELL, FRHT, OTHR, and RAM, each with 1 citation. The small sample size (2 total citations) makes a clear pattern difficult to identify, but the presence of FRHT (Freightliner) suggests commercial tank vehicles used in hazmat transport. If you operate a pressurized hazmat tank under an MC338 placard, you should ensure the pressure relief device meets all specifications regardless of manufacturer.
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