# Umicore USA, Inc — Hazardous Materials Safety Interpretation **Citation:** 07-0173 **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2007-09-21 07-0173 response to Umicore USA, Inc concerning 172.101. ## Document text <<>> of Transportation U.S. Department 1200 New Jersey Avenue, S.E. Materials Safety Administration Pipeline and Hazardous Washington, D.C. 20590 SEP 21 2007 Mr. Gary Sommer Ref. No.: 07-0173 Jmicore USA. Inc Environmental Health and Safety Manage P.O. Box 5097 4261 Mainway Drive Burlington, Ontario Canada L7R 3Y8 Dear Mr. Sommer: This is in response to your August 21, 2007 letter requesting clarification of the Hazardous lefinition of a hazardous substance. Specifically, you ask if the method you use to determine th Materials Regulations (HMR; 49 CFR Parts 171-180) for determining if a material meets thi particle diameter of your zinc powder is acceptable under the HMR. In your letter, you state that you use a laser diffraction method to determine the particle size of your zinc powder. You are correct in your understanding that there are no requirements under the HMR specifying how the particle size must be determined. Under the HMR, zinc meets the package and when the metal particles have a diameter smaller than 100 micrometers (0.004 detinition of a hazardous substance when more than one thousand pounds is contained in one inches). Any method used to determine the metal particle diameter, including the laser diffraction method described in your letter, is acceptable. I hope this information is helpful. If you have further questions, please do not hesitate to contact this office. Sincerely. takin Chief, Regulatory Review and Reinvention Hattie L. Mitchell Office of Hazardous Materials Standards 172-101 A 070173 <<>> Hollack § 12.101 App.A Reportable Quantitlicore 07-0174 materials for a batter life TO: Mr. Ed Mazzullo, Director U.S. Department of Transportation August 21, 2007 Pipeline and Hazardous Materials Safety Administration Office of Hazardous Materials Safety Washington, DC 20590 From: Gary Sommer Umicore USA Inc. Branch office: 4261 Mainway Drive Burlington, Ontario Canada L7R 3Y8 Re: Method for determining particle size for RQ requirements Dear. Mr. Mazzullo: Our company is an international manufacturer and importer of zinc based powders. The zinc powder is listed in 49 CFR §172. 101 Appendix A with an RQ of 1000 laving a diameter smaller than 100 micrometers (0.004 inches). We would like to ounds and a foot note indicating that the RQ is limited to those pieces of the meta contirm in writing that in order to determine the particle size of the said zinc powder we can use a laser diffraction method, which is generally recognized as the most effective and reproducible means for determining particle size for fine powders. In past correspondence with a Mr. Bob Richard, (e-mail dated June 12, 2001); Mr. particle size must be determined. He also indicated that since no specific method is Richard indicated that there are no guidelines or requirements specifying how the mentioned the laser diffraction method is acceptable. methods for determining particle size. Could you please confirm this statement or provide an interpretation of acceptable Sincerely, Gary Sommer North American EHS Manager Gary Sommer Umicore USA Inc. T 905-336-3424 × 2508 F 905-319-4169 ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `a3b7ae6f247647cae803022bbaebf60f28012d4017e71419ab975053d6a77740` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-23T10:47:54.642Z - Document slug: `phmsa-interpretation-07-0173` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [ "Umicore USA, Inc" ], "individuals": [ "Mr. Gary Sommer" ], "refIds": [ "07-0173" ], "catalogDates": [ "2007-09-21" ], "catalogParts": [ 172 ], "catalogRowCount": 1, "sourceRecordUrls": [ "https://www.phmsa.dot.gov/node/59746" ], "linkedAttachmentUrls": [], "unavailableResponseUrls": [], "duplicateRepresentationUrls": [], "citedSections": [ "172.101" ], "catalogPageUrls": [ "https://www.phmsa.dot.gov/regulations/title49/section/172101" ], "pdfUrls": [ "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2007/070173.pdf" ], "representations": [ { "viewUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2007/070173.pdf", "detailUrl": null, "detailHtmlPath": null, "pdfUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2007/070173.pdf", "pdfArtifactPath": "data/sources/phmsa-interpretations/07-0173-cf6be3ac63.pdf", "pdfArtifactSha256": "2c60e12a7c2411b76516e2033383c6a2f0e23a4769ecae2853d17a2f7381bf61", "extractedTextPath": "data/sources/phmsa-interpretations/07-0173-cf6be3ac63.v2.txt", "extractedTextSha256": "b9efd3df00955115741b5d05c773a22ddd74be3e885553e6f28b95ef9dd9d614", "pageCount": 2, "extractionVersion": 2 } ], "caveat": "Interpretations apply regulations to the facts presented and do not create independently enforceable requirements.", "jurisdiction": "US" } ```