New hazmat rule allows shipping refrigerating machines with low-flammability gases

A new hazmat rule changes shipping requirements for refrigerating machines and their components. The final rule updates 49 CFR 173.306 to include the terms of DOT Special Permit 21379.

Carriers and shippers may now transport up to 5,000 pounds of low flammability refrigerants in these machines. The allowance applies to Category 1B refrigerants under the Globally Harmonized System or Group A2L refrigerants under ANSI/ASHRAE Standard 34. Companies no longer need to apply for a special permit to ship these loads.

The rule becomes effective on September 3, 2026. Offerors and carriers can begin using the new exception thirty days after publication.

PHMSA incorporated ANSI/ASHRAE Standard 34-2024 and the Globally Harmonized System of Classification and Labelling of Chemicals, 9th Revised Edition, by reference. These documents list the specific refrigerants that qualify for the exception.

Source: Federal Register — https://www.federalregister.gov/documents/2026/08/04/2026-15818/hazardous-materials-adoption-of-department-of-transportation-special-permit-21379