What 173.315A means in plain language
FMCSR 173.315A addresses the general requirements that apply to Class 2 hazardous materials when they are transported in cargo tanks or portable tanks. Class 2 materials include compressed gases, liquefied gases, and dissolved gases—substances that require pressurized containment and special handling.
The regulation requires that cargo tanks and portable tanks meet specific design, construction, and operational standards before they can legally carry these materials. This isn't about how you load or unload; it's about the tank itself. Your vehicle's tank must be properly certified, maintained, and equipped to safely contain Class 2 hazmat under all conditions—pressure spikes, temperature changes, rough road conditions, and accident scenarios.
If an inspector finds that your tank doesn't meet Class 2 general requirements—whether that's a certification issue, structural defect, missing safety equipment, or improper modification—you'll be cited. The specific violation depends on what was wrong with the tank itself, not your driving or documentation practices.
What our enforcement data actually shows
Across our 13 million+ inspection records, 173.315A is a rare citation. We've recorded 2 all-time citations for this code, with 1 citation in the last 12 months and 1 in the last 90 days. This makes 173.315A ranked #2651 out of 3,036 FMCSR codes by total citation volume.
Out-of-service enforcement is uncommon here: 0 vehicles were placed out of service, giving 173.315A a 0.0% OOS rate across all time. This is significantly lower than the all-FMCSR average OOS rate of 31.4%. The low volume and zero OOS rate suggest that either hazmat tank operators are generally compliant with Class 2 requirements, or inspectors identify and correct these issues before escalating to out-of-service status.
The rarity of this citation doesn't mean the risk is zero—it reflects that Class 2 cargo tank transport is a specialized operation with fewer operators and stricter pre-operation protocols than general trucking.
Who gets cited most
Our inspection records show citation activity concentrated in one state over the last 180 days. Texas recorded 1 citation with a 0.0% out-of-service rate. The extremely small sample size means state-level patterns are not yet statistically meaningful for prediction or comparison.
At the carrier level, our all-time data identifies two fleets with Class 2 tank citations: AUTOLINEAS PERZA SA DE CV (USDOT 3346939) and ANTRIAVI SA DE CV (USDOT 3524907), each with 1 citation. These figures reflect the specialized nature of Class 2 hazmat transport—only a subset of carriers operate the equipment required for these materials.
How severe is this compared to similar codes
173.315A sits within the broader hazardous materials compliance ecosystem. Comparing it to related codes reveals important context:
177.834A-HMC (General loading/unloading hazmat) has generated 3,954 citations all-time with a 99.2% out-of-service rate. This code addresses how hazmat is handled during transport operations—a much higher-volume violation area with severe enforcement consequences.
172.502(a)(1) (Placarding general requirements) has 1,820 all-time citations and an 18.5% OOS rate. Placarding violations are far more common than cargo tank structural defects, likely because labeling failures are easier to occur during routine operations.
172.602(c)(1) (Maintenance/accessibility of Emergency Response information) parallels 173.315A with 1,464 citations and a 0.0% OOS rate. Like Class 2 tank requirements, this code focuses on compliance with equipment standards rather than operational mistakes, resulting in rare out-of-service placement.
The pattern suggests that tank and equipment compliance violations (like 173.315A) trigger lower enforcement escalation than operational or loading violations, possibly because inspectors expect hazmat carriers to have these matters resolved before operation begins.
How to avoid it
Since 173.315A concerns the physical tank and its certification rather than your driving decisions, prevention starts long before you pull out:
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Verify tank certification before accepting the load. Review DOT certification documents, manufacturer specs, and inspection records. Confirm that the tank is DOT-certified for Class 2 service and that certification is current. A tank certified for Class 3 liquids may not be legal for Class 2 gases.
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Conduct a thorough pre-trip inspection of the tank exterior. Look for visible damage, corrosion, dents, or deformations that could compromise pressure integrity. Check that all inspection ports, pressure relief valves, and safety vents are present and secure. Our data shows that in inspections where 173.315A was cited, emergency equipment deficiencies like missing fire extinguishers (code 393.95A1I) co-occurred, indicating that tank compliance and safety gear go hand-in-hand.
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Confirm all required placards and labels are in place and legible. While placarding is technically a separate code, carriers cited for tank defects often have documentation gaps. Ensure the HAZMAT placard clearly identifies the Class 2 material and any subsidiary hazard.
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Know your tank's rated capacity and pressure limits. Never exceed the design specifications, even if instructed. Class 2 tanks are pressurized by definition; exceeding limits creates immediate danger and citation risk.
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Request recent maintenance and inspection records from the carrier. If your company operates the tank, maintain detailed logs of inspections, repairs, and any modifications. Unauthorized modifications or deferred maintenance are common citation triggers.
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Ask dispatch about the tank's service history. If a tank has been involved in an accident, overpressure event, or repair work, confirm that it has been re-certified before hauling Class 2 materials.
The rarity of 173.315A citations reflects that most hazmat carriers invest in proper equipment because the consequences of a Class 2 tank failure are severe. Your job is to trust but verify—know your tank's status before you drive it.