PHMSA's September 28 final rule authorizes ASME Section XII and the 2015 National Board Inspection Code for specified cargo tank motor vehicles and other transport tanks, effective October 28.
PHMSA published the final rule on September 28
The Pipeline and Hazardous Materials Safety Administration published final rule HM-241 in the Federal Register on September 28, 2026. It updates the Hazardous Materials Regulations in 49 CFR parts 107, 171, 173, 178, 179 and 180 by incorporating transport-tank construction and continued-service standards.
The rule becomes effective October 28
The final rule's effective date is October 28, 2026. PHMSA allows voluntary compliance beginning September 28, the publication date, and the Director of the Federal Register approves the incorporated materials as of October 28. Fleets should distinguish that optional early-use date from the rule's effective date.
ASME Section XII becomes an additional construction path
PHMSA authorizes the 2015 edition of ASME Boiler and Pressure Vessel Code Section XII, which was developed specifically for the construction and continued service of transport tanks. It is an alternative to the existing Section VIII, Division 1 route, not a mandatory replacement for every newly built tank.
Five cargo-tank specifications are covered
For cargo tank motor vehicles, the authorized specifications are MC 331 and MC 338 plus DOT 406, DOT 407 and DOT 412. The rule also covers UN T75 cryogenic portable tanks and DOT 106A and 110AW multi-unit tank car tanks. It does not make Section XII a universal option for every container or truck body.
The 2015 NBIC governs continued service for Section XII tanks
A cargo tank motor vehicle built under Section XII must use the 2015 National Board Inspection Code Parts 2 and 3, including Supplement 6, for continued service. PHMSA says these materials address inspection, repair, alteration, reporting, document control and inspector responsibilities for transport tanks.
Existing Section VIII tanks keep a choice
For a cargo tank motor vehicle built to ASME Section VIII, Division 1, the final rule keeps the applicable Part 180 requirements and allows the 2015 NBIC or the previously incorporated 1992 NBIC as applicable. An owner should identify the tank's original construction standard before selecting an inspection or repair path.
The rule is permissive rather than a fleet retrofit order
PHMSA characterizes the final rule as deregulatory and says it imposes no new costs. It does not order carriers to rebuild existing cargo tanks to Section XII or replace Section VIII tanks on October 28. It creates additional authorized standards, subject to the detailed conditions, limitations and exceptions in the amended regulations.
PHMSA estimates $8.1 million in annualized savings
The agency estimates annualized net savings of about $8.1 million using a seven-percent discount rate. PHMSA attributes the benefit to more construction and continued-service options, potential design efficiencies and less need for special permits. That is an agency-wide estimate, not a promised saving for every tank owner.
The rule responds to long-running industry petitions
The action completes a rulemaking that began after industry petitions and earlier proposals dating to 2010. PHMSA says the final version addresses three petitions and two National Transportation Safety Board recommendations arising from a cargo tank rollover and fire involving liquefied petroleum gas.
PHMSA says Section XII better reflects transport stresses
The preamble explains that Section VIII was written for stationary boilers and pressure vessels and requires additional HMR provisions when applied to transport tanks. Section XII builds on that foundation but is designed for transport conditions and includes continued-service standards. PHMSA says the alternative can improve regulatory flexibility without compromising safety.
Drivers do not receive a new operating exemption
The final rule concerns design, construction, qualification, maintenance, inspection, repair and related records for covered transport tanks. It does not waive CDL or hazardous-material endorsement requirements, shipping-paper duties, loading controls, hours-of-service rules, route restrictions, attendance requirements or safe-driving obligations.
Carriers should inventory each tank before changing procedures
Record the specification, manufacturer, serial number, construction code, date, current qualification status and facility responsible for testing or repair. Then compare the amended HMR and incorporated standard with existing procedures, contracts, inspector qualifications, repair authorizations, markings and record systems. Do not infer the correct path from cargo type alone.
Repair facilities need the exact code and authorization
A facility should verify which code edition and HMR provisions govern the tank before inspecting, repairing or altering it. The Section XII and NBIC options have conditions and exceptions that a summary cannot reproduce. Owners should obtain the controlling standards and use properly qualified personnel rather than treating the new option as blanket permission for an alternate repair.
Primary-source note
This report is based on Federal Register document 2026-19741, published September 28, 2026. CDL Truck Pro has described Section XII and the 2015 NBIC as authorized alternatives for specified transport tanks, not as an immediate retrofit mandate or an operating waiver, and has separated voluntary compliance from the October 28 effective date.
Continue with CDL Truck Pro
Official sources
Federal Register: PHMSA final rule HM-241, September 28, 202649 CFR Part 180: Continuing qualification and maintenance of packagingsPHMSA: Cargo Tank Safety ResourcesCDL Truck Pro provides educational information. Confirm licensing, safety, tax, and regulatory requirements through current official sources and qualified professionals.