The Nickel Report

Among the changes, the proposed rule would amend Hazardous Materials Regulations to treat sodium ion batteries in a manner similar to the way lithium ion batteries are regulated.

On February 10, 2026, the Pipeline and Hazardous Materials Safety Administration (PHMSA) published a notice of proposed rulemaking (NPRM) to amend the Hazardous Materials Regulations (HMR) to adopt certain international regulations and standards concerning proper shipping names, hazard classes, packing groups, special provisions, packaging authorizations, air transport quality limitations, and vessel stowage requirements. Notably, in this NPRM, PHMSA recognizes the increased use of sodium ion batteries and proposes various changes to regulate them in the same manner as lithium ion batteries.

The proposed changes will promote global consistency for the transportation of hazardous materials and may reduce costs for entities and individuals in the US. If issued as a final rule, these adoptions will have far-reaching impacts, particularly with respect to batteries. PHMSA is accepting public comment on this NPRM until April 13, 2026.

Background

PHMSA is part of the United States Department of Transportation and is responsible for regulating and promoting safe transportation of energy and other hazardous materials. Federal Hazardous Materials Transportation Law directs PHMSA to participate in international standard-setting forums for transporting hazardous material in international commerce and encourages consistency between HMR and international standards, when possible.^[1]

In 1990, the HMR were comprehensively revised in accordance with the UN Model Regulations, which are amended and updated every two years. The UN Model Regulations serve as the basis for national, regional, and international modal standards, including the International Civil Aviation Organization Technical Instructions for the Safe Transport of Dangerous Goods by Air (ICAO Technical Instructions) and the International Maritime Dangerous Goods Code (IMDG Code). PHMSA has routinely updated the HMR in response to these biennial amendments and related standards.

The most recent updates to the UN Model Regulations, ICAO Technical Instructions, and the IMDG Code were published by or in effect on January 1, 2025.

PHMSA Proposes to Amend HMR to Reflect Recent Changes to International Standards

PHMSA has undergone its evaluation of the latest biennial updates to the international regulations and standards. Accordingly, PHMSA proposes to revise the HMR to adopt changes consistent with changes to the 2025-2026 edition of the ICAO Technical Instructions, the Amendment 42-24 to the IMDG Code, and the 23rd revised edition of the UN Model Regulations. Additionally, PHMSA proposes to incorporate by reference these amended international regulations, as well as several new or updated International Organization for Standardization (ISO) standards. The most noteworthy proposed changes include the following:

• New provisions for sodium ion batteries. PHMSA proposes to add new hazardous materials table entries and transport provisions for sodium ion batteries to reflect changes adopted in the 2025-2026 edition of the ICAO Technical Instructions and the 23rd revised edition of the UN Model Regulations. Specifically, these new provisions would regulate sodium ion batteries in the same manner as lithium ion batteries and account for the increased use of sodium ion batteries.
• Amendments to the hazardous materials table. PHMSA proposes to amend the Hazardous Materials Table at 49 C.F.R. 172.101 to add, revise, or remove certain proper shipping names, hazard classes, packing groups, special provisions, packaging authorizations, bulk packaging requirements, and passenger and cargo aircraft maximum quantity limits. For example:
  • PHMSA proposes to add three new entries for sodium ion batteries: UN3551, Sodium ion batteries with organic electrolyte; UN3552, Sodium ion batteries contained in equipment, with organic electrolyte; and UN3552, Sodium ion batteries packed with equipment, with organic electrolyte. PHMSA anticipates that these new entries will provide a baseline of uniform transport standards for sodium ion batteries, which is especially important given the increase use of sodium ion batteries as an alternative to lithium ion batteries.
  • PHMSA proposes to add three new entries for vehicles powered by lithium ion batteries, lithium metal batteries, and sodium ion batteries: UN3556, Vehicle, lithium ion battery powered; UN3557, Vehicle, lithium metal battery powered; and UN3558, Vehicle, sodium ion battery powered. PHMSA anticipates that these additions are necessary to address the market growth in personal mobility devices, such as e-bikes, e-scooters, and other lightweight vehicles.
• Increase in authorized amounts of certain gases transported as limited quantities. For modes other than air transportation, PHMSA proposes to extend the relief provided by the limited quantity provisions for UN1013, Carbon Dioxide; UN 1046, Helium; and UN1066, Nitrogen. This change would authorize these compressed gases to be transported as limited quantity materials up to 1000 ml per package when transported in certain DOT or UN containers.
• Amendments to the organic peroxides table. PHMSA proposes additions to the organic peroxides table at 49 C.F.R. 173.225. Specifically, PHMSA proposes to add three new formulations that will no longer require prior approval when transported in accordance to the table. Additionally, PHMSA proposes to add a new authorized packaging for Di-(3,5,5,-trimethylhexanoyl) peroxide, not more than 52 percent, stable dispersion, in water.
• Amendments to provisions for the transport of tetramethylammonium hydroxide. In response to new incident and test data and changes adopted in international standards, PHMSA proposes to adopt several changes related to entries for tetramethylammonium hydroxide (TMAH). Proposed revisions include the addition of a new hazardous materials table entry for aqueous solutions and revisions to the hazard classification, proper shipping name, reclassification of TMAH solids, the addition of two special provisions, and revised packaging authorizations.
• New state-of-charge provisions for certain lithium and sodium ion batteries transported by air. PHMSA proposes to expand state-of-charge requirements for certain lithium and sodium batteries transported by air, by limiting the amount of stored energy to 30 percent or less of the battery’s capacity at the time of transport.
• Improved emergency response information for lithium batteries transported as “UN3526, lithium batteries installed in cargo transport unit lithium ion batteries or lithium metal batteries.” PHMSA proposes to amend Special Provision 389 to require that emergency response information for lithium batteries installed in a cargo transport unit (UN 3536) identify the predominant type of battery (e.g., lithium ion batteries or lithium metal batteries) and provide safety information for handling fires.
• Exceptions of ammonium nitrate hot concentrated solution. Consistent with the 23rd revised edition of the UN Model Regulations, PHMSA proposes to add specific conditions under which ammonium nitrate can be transported under hazardous materials table entry UN2426, Ammonium nitrate, or can qualify for exception from regulation.
• Exceptions for nitrocellulose membrane filters used in rapid test devices. Also consistent with the 23rd revised edition of the UN Model Regulations, PHMSA proposes to add a new special provision with specific packaging requirements for certain nitrocellulose membrane filters, which are most commonly used for rapid test devices for infectious diseases and pregnancy tests, to be excepted from regulation.

PHMSA anticipates that these proposed changes will  harmonize HMR and international standards, producing safety benefits and decreasing transportation costs for individuals and entities in the US. Among other things, PHMSA is seeking comment on the need, benefits, and costs of the proposed HMR revisions; impact on safety and the environment; approaches to improve rulemaking; and any other relevant information. Comments must be received by April 13, 2026.

Contact Brian Stansbury at bstansbury@hunton.com with questions about PHMSA’s NPRM or interest in submitting comments.

[1] 49 U.S.C. § 5120.