Transportation/Hazardous Materials: U.S. Pipeline and Hazardous Materials Safety Administration Interpretive Letter Addressing Mower/Lithium Battery Requirements
June 16, 2026
By:
Walter G. Wright
Category:
Arkansas Environmental, Energy, and Water Law
Arkansas Environmental, Energy, and Water Law
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The Pipeline and Hazardous Materials Safety Administration (“PHMSA”) addressed in an April 29th interpretive letter the application of the federal Hazardous Materials Regulations (“HMR”) applicable to the transportation of lithium batteries contained in equipment. See Reference No. 25-0132.
PHMSA was responding to an October 1, 2025 letter from National Transportation Consultants (“NTC”) requesting clarification on the labeling and marking requirements for an unpackaged riding mower containing a large lithium battery transported on a trailer.
PHMSA initially notes that under § 173.22, it is the shipper's responsibility to classify a hazardous material properly (in accordance with classification criteria provided in the HMR) prior to offering it for transportation to—or within—the United States.
Nevertheless, it states that based on the scenario in NTC’s letter, the riding mower may be described under the Hazardous Materials Table entry “UN3171, Battery-powered vehicle or Battery-powered equipment, 9.” Therefore, when transported in accordance with the provisions of § 173.220, such vehicles are excepted from the marking and labeling requirements of 49 CFR Part 172, Subparts D and E.
A copy of the interpretive letter can be found here.
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