# Tesla — Hazardous Materials Safety Interpretation - **operation:** document - **citation:** 25-0031 - **title:** Tesla — Hazardous Materials Safety Interpretation - **source type:** guidance - **agency:** Pipeline and Hazardous Materials Safety Administration - **status:** guidance - **official:** true - **published on:** 2025-06-05 - **effective on:** Not available - **summary:** 25-0031 response to Tesla concerning 173.185. - **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-25-0031.json - **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-25-0031.md - **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-25-0031 - **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2025-06/250031.pdf **body:** <<>> 1200 New Jersey Avenue, SE Washington, DC 20590 U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration June 5, 2025 Ryan Bush, Engineering Supervisor, Tesla 1 Electric Ave Reno, NV 89434 Reference No. 25-0031 Dear Mr. Bush: This letter is in response to your March 17, 2025 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to United Nations specification packaging exceptions for lithium cells and batteries. Specifically, is there a definition for “strong, impact-resistant outer casing” in the HMR? No. There is not a specific definition for “strong, impact-resistant outer casing” in the HMR. Section 173.185(b)(5) allows shippers to package lithium cells or batteries, weighing 12 kg or more with strong, impact-resistant outer casing, using alternative packaging that demonstrates equivalency to the performance standards of Packing Group (PG) II. Furthermore, lithium cells or batteries must be secured to prevent damage caused by inadvertent shifting, the terminals must not support the weight of other superimposed elements, and the packaging must prevent short circuits.1 Note that PHMSA has previously interpreted2 the meaning of “strong, impact- resistant outer casing” for these batteries. It is the shipper’s responsibility to ensure the packaging, enclosures, or other handling devices meet necessary performance standards (i.e., to withstand normal conditions incident to transportation). I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely, Dirk Der Kinderen Chief, Standards Development Branch Standards and Rulemaking Division 1 See also § 173.185(b)(2). 2 See letters Ref. Nos. 19-0080, 23-0045, 23-0088, and 23-0091. <<>> Baker, Y. 25-0031 From: INFOCNTR (PHMSA) To: Dodd, Alice (PHMSA) Cc: Hazmat Interps; Baker, Yul (PHMSA) Subject: FW: 173.185b Interpretation Date: Monday, March 17, 2025 16:08:28 Attachments: image001.png Good Afternoon, See the attached interpretation request. Let me know if anything else is needed. Best, Aminah From: Ryan Bush Sent: Monday, March 17, 2025 12:10 PM To: INFOCNTR (PHMSA) Subject: 173.185b Interpretation You don't often get email from rybush@tesla.com. Learn why this is important CAUTION: This email originated from outside of the Department of Transportation (DOT). Do not click on links or open attachments unless you recognize the sender and know the content is safe. Good morning, I’m reaching out to request an interpretation on the exception for UN-specification packaging for Li-ion batteries. It states “Lithium cells or batteries that weigh 12 kg (26.5 pounds) or more and have a strong, impact-resistant outer casing, may be packed in strong outer packagings; in protective enclosures (for example, in fully enclosed or wooden slatted crates); or on pallets or other handling devices, instead of packages meeting the UN performance packaging requirements in paragraphs (b)(3)(ii) and (b)(3)(iii) of this section. Cells and batteries must be secured to prevent inadvertent shifting, and the terminals may not support the weight of other superimposed elements. Cells and batteries packaged in accordance with this paragraph may be transported by cargo-only aircraft if approved by the Associate Administrator.” Specifically, I’m trying to understand the requirements/definition of the “strong, impact- resistant outer casing” statement. Is this arbitrary, to be determined (reasonably/in good faith) by the Shipper, or is there an exact definition of this somewhere? Thank you for your time. Respectfully, Ryan Bush | Engineering Supervisor, Cell Quality & Field Reliability <<>> 1 Electric Ave Reno, NV 89434 m. +1 (650) 489-8758 | rybush@tesla.com The content of this message is the proprietary and confidential property of Tesla Motors, and should be treated as such. If you are not the intended recipient and have received this message in error, please delete this message from your computer system and notify me immediately by reply e-mail. Any unauthorized use or distribution of the content of this message is prohibited. Thank you. P Please consider the environment before printing this email - **truncated:** false - **body characters:** 4293