Interpretation Response #25-0145
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Fluence
Individual Name: Anna Stephens
Location State: GA Country: US
View the Interpretation Document
Response text:
January 29, 2026
Anna Stephens
Sr. Commodity Manager, Logistics
Fluence
1725 Windward Concourse #420
Alpharetta, GA 30005
Reference No. 25-0145
Dear Ms. Stephens:
This letter is in response to your October 3, 2025, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the transport of lithium ion batteries in cargo transport units (CTUs).
We have paraphrased and answered your questions as follows:
Q1. Are placards required when shipping an energy storage system classified as "UN3536, Lithium batteries installed in cargo transport unit, 9." If the answer is yes, what type of placards are required to be placed on the CTU?
A1. Yes. As provided in Special Provision (SP) 389 in § 172.102, a CTU must display the UN number in a manner in accordance with § 172.332 and be placarded on two opposing sides with a Class 9 placard.
Q2. If placarded, is the driver of a motor vehicle transporting an energy storage system classified as "UN3536, Lithium batteries installed in cargo transport unit, 9" required to have a hazmat endorsement on his or her commercial driver’s license (CDL).
A2. The endorsement requirements for a CDL (see 49 CFR Part 383.91(a)(3)) are under the purview of the Federal Motor Carrier Safety Administration (FMCSA). FMCSA is the lead federal government agency responsible for regulating and providing safety oversight of commercial motor vehicles. You may wish to contact FMCSA should you require clarification of any requirements relevant to CDLs.
Q3. Are there any rulemaking proposals to require the placarding of an energy storage system classified as "UN3536, Lithium batteries installed in cargo transport unit, 9" under subpart F of 49 CFR part 172.
A3. No rulemakings are in progress to revise the placarding requirements applicable to lithium batteries in CTUs. See answer A1.
Q4. What are the requirements for fire extinguishers that are necessary within the CTU, as provided in SP 389?
A4. In accordance with SP 389, hazardous materials necessary for the safe and proper operation of the CTU (e.g., fire extinguishing systems and air conditioning systems) must be properly secured to or installed in the CTU and are not otherwise subject to the HMR. However, packagings (e.g., a DOT specification cylinder) represented as meeting requirements of the HMR governing their use in the transportation of a hazardous material must be so maintained unless representative marks are obliterated or covered (see § 171.1(g)).
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk DerKinderen
Chief, Standards Development Branch
Standards and Rulemaking Division