The Pipeline and Hazardous Materials Safety Administration has released a notice of proposed rulemaking to revise the Hazardous Materials Regulations. This action seeks to incorporate updates from key international standards, including the 2025-2026 ICAO Technical Instructions, Amendment 42-24 of the IMDG Code, and the 23rd revised edition of the UN Model Regulations. Published on February 10, 2026, in the Federal Register, the proposal addresses proper shipping names, hazard classifications, packaging authorizations, and transport limitations. These changes are designed to align domestic rules with global practices, reducing regulatory burdens and enhancing safety in hazardous materials transportation. Comments are due by April 13, 2026, with potential consideration of late submissions.
Background and Key Players
The proposal stems from statutory mandates under 49 U.S.C. 5120, directing the Secretary of Transportation to harmonize U.S. regulations with international standards where feasible. PHMSA, part of the Department of Transportation, actively participates in bodies like the UN Sub-Committee of Experts on the Transport of Dangerous Goods. This NPRM reflects biennial updates to standards developed through international collaboration, informed by incident data and technological advancements.
Relevant legal precedents include prior harmonization rulemakings, such as HM-215Q, which addressed similar alignments. Political forces include ongoing emphasis on regulatory efficiency, with any executive orders attributed to President Trump. The primary stakeholders are shippers, carriers, manufacturers, and emergency responders, who benefit from reduced compliance complexities.
Major Proposed Amendments
PHMSA proposes incorporating updated international standards by reference, including the 2025-2026 ICAO Technical Instructions and the 23rd UN Model Regulations. This would replace outdated versions in the HMR, ensuring consistency in areas like air transport quantity limits and vessel stowage.
Amendments to the Hazardous Materials Table include new entries for sodium ion batteries (UN3551 and UN3552), fire suppressant dispersing devices (UN0514 and UN3559), and revisions for tetramethylammonium hydroxide (TMAH). For TMAH, toxicity data prompted reclassification, with new special provisions 408 and 409 for hazard communication and transition periods. As quoted in the NPRM, 'human exposure and toxicity studies have demonstrated that solid TMAH has a significant toxicity hazard.'
Other changes expand limited quantity provisions for certain Division 2.2 gases up to 1000 ml per package, excluding air transport, and add exceptions for nitrocellulose membrane filters used in medical testing. New state-of-charge limits for lithium and sodium ion batteries by air aim to mitigate thermal runaway risks.
Short-Term and Long-Term Implications
In the short term, these amendments could streamline compliance for international shipments, potentially reducing delays at ports. For instance, harmonized TMAH classifications may prevent mis-shipments, enhancing safety for handlers. Perspectives vary: industry groups may welcome cost reductions, while safety advocates emphasize the need for robust testing, as in the UN Manual of Tests and Criteria.
Long-term, the rule supports emerging technologies like sodium ion batteries, fostering innovation in energy storage without compromising safety. However, increased regulatory alignment might challenge smaller entities adapting to changes. Broader debates include balancing economic efficiency with environmental protections, given hazardous materials' potential impacts.
Perspectives and Debates
Stakeholders offer diverse views. Manufacturers support expanded packaging options for organic peroxides, citing reduced approval needs. Emergency responders appreciate clearer hazard communication for batteries, as in Special Provision 389. Critics, however, question exceptions for untested prototypes, arguing for stricter oversight. The NPRM avoids endorsing positions, focusing on verifiable data from sources like the UN Sub-Committee.
Potential challenges include implementation timelines, with transitional periods like Special Provision 409 allowing until December 31, 2026, for TMAH adjustments. Ongoing debates center on air transport risks, with ICAO's state-of-charge limits sparking discussions on feasibility versus safety.
Key takeaways from this proposed rule include enhanced global consistency in hazardous materials transport, potential cost savings through regulatory alignment, and targeted safety improvements for emerging technologies. The amendments reflect a balanced approach to maintaining safety while facilitating commerce.
Possible next steps involve public comments shaping the final rule, with PHMSA considering late submissions. Future challenges may include adapting to rapid technological changes, such as advanced battery chemistries, and addressing enforcement gaps. Debates will likely focus on balancing innovation with risk mitigation, potentially leading to further international collaborations.
