Federal law overrides California propane cylinder rule

Federal law now overrides a California rule about propane cylinders. This decision applies to carriers that transport propane in or to California.

California passed a law requiring all propane cylinders sold in the state on or after January 1, 2028, to be reusable or refillable. Federal hazardous materials regulations already authorize DOT-39 cylinders that are designed to be non-reusable and non-refillable.

The agency found that the state rule conflicts with federal safety standards. Banning federally approved packaging creates a fragmented regulatory system. Carriers can continue to ship propane using DOT-39 non-reusable cylinders that meet federal requirements.

The decision follows a request from Worthington Enterprises, Inc. The agency published the request in January 2026 and accepted comments until March 10, 2026. PHMSA received seventeen comments before making this determination.

Source: Federal Register — https://www.federalregister.gov/documents/2026/09/10/2026-18501/hazardous-materials-californias-reusability-mandate-for-propane-cylinders