# Teledyne Scientific & Imaging — Hazardous Materials Safety Interpretation - **operation:** document - **citation:** 25-0017 - **title:** Teledyne Scientific & Imaging — Hazardous Materials Safety Interpretation - **source type:** guidance - **agency:** Pipeline and Hazardous Materials Safety Administration - **status:** guidance - **official:** true - **published on:** 2025-04-08 - **effective on:** Not available - **summary:** 25-0017 response to Teledyne Scientific & Imaging concerning 172.101, 173.22. - **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-25-0017.json - **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-25-0017.md - **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-25-0017 - **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2025-04/250017.pdf **body:** <<>> U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration April 8, 2025 1200 New Jersey Avenue, SE Washington, DC 20590 Jennifer Kuo Teledyne Scientific & Imaging 1049 Camino Dos Rios Thousand Oaks, CA 91360 Reference No. 25-0017 Dear Ms. Kuo: This letter is in response to your February 11, 2025 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the use of the United Nations (UN) identification number and proper shipping name “UN1396, Aluminum powder, uncoated.” Specifically, you ask if there is a particle size limit with respect to the use of this hazardous materials description. No. While certain hazardous materials descriptions and proper shipping names in the § 172.101 Hazardous Materials Table (HMT) limit use of the entry (e.g., a concentration range, particle size, energy capacity, etc.), the entry for “UN1396, Aluminum powder, uncoated” does not specify limiting criteria for particle size. Furthermore, the test method in the UN Manual of Tests and Criteria do not specify a particle size. Hazardous materials that may be dangerous when wet, such as aluminum powder, uncoated, are classified based on the results of testing (i.e., UN Test N.5, Test method for substances which in contact with water emit flammable gases, see Section 33.5 of the UN Manual of Tests and Criteria) irrespective of particle size. Ultimately, as provided in § 173.22, it is the shipper’s responsibility to properly classify and describe a hazardous material based on the classification criteria provided in the HMR. 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 <<>> Casey 25-0017 From: INFOCNTR (PHMSA) To: Dodd, Alice (PHMSA) Cc: Hazmat Interps Subject: FW: Request for letter of interpretation Date: Wednesday, February 12, 2025 12:02:33 PM Good afternoon Alice, See the attached interpretation request. Let us know if you need anything else. Best, Aminah From: Kuo, Jennifer (US) Sent: Tuesday, February 11, 2025 3:59 PM To: INFOCNTR (PHMSA) Subject: Request for letter of interpretation You don't often get email from jennifer.kuo@teledyne.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. Hello, I would like to request a letter of interpretation on the specific description of UN 1396, Aluminum powder, uncoated. I am looking for the particle size that this UN number covers. Specifically, I would like to know how large a particle is considered a powder with respect to this UN designation. I have not been able to find the particle size defined for this particular chemical. Please send the information to: Jennifer Kuo Teledyne Scientific 1049 Camino Dos Rios Thousand Oaks, CA 91360 (805)373-4536 Jennifer.Kuo@teledyne.com Please let me know if you have questions on my request. Thank you, Jennifer Kuo <<>> Jennifer.Kuo@teledyne.com (805)373-4536 Teledyne Scientific & Imaging Teledyne Confidential; Commercially Sensitive Business Data - **truncated:** false - **body characters:** 3345