The United States Pipeline and Hazardous Materials Safety Administration (“PHMSA”) clarified in a July 29th Interpretive Letter the federal Hazardous Materials Regulations (“HMR”) applicable to hazmat registration for lithium batteries that comprise a battery energy storage system (“BESS”). See Reference No. 25-0051.
PHMSA was responding to an April 7, 2025 letter from the Iowa Department of Public Safety (“Iowa”) in which it described a scenario involving lithium batteries, installed in a Cargo Transport Unit (“CTU”).
A bill of lading enclosed with Iowa’s letter indicated that the dimensions of the cargo transport unit were 19.11 feet long, 8.08 feet wide, and 9.07 feet tall (approximately 1,400 cubic feet), weighing approximately 77,000 pounds.
Iowa asked whether this CTU would be considered a bulk packaging under the definition in § 171.8.
PHMSA responds in the affirmative, stating that as defined in § 171.8, bulk packaging is defined as a packaging, other than a vessel or a barge, including a transport vehicle or freight container, in which hazardous materials are loaded with no intermediate form of containment. It further stated that because the batteries described are housed within a single container, and wired together as a single unit, rather than being separated into individual inner packages, the container is considered a bulk packaging.
PHMSA also notes that registration is required under § 107.601(a)(4) for any shipment of hazardous materials in a bulk packaging that has a capacity of at least 13.24 cubic meters for solids.
A copy of the Interpretive Letter can be found here.
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