# Evonik Degussa Corporation — Hazardous Materials Safety Interpretation **Citation:** 08-0291 **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2009-02-11 08-0291 response to Evonik Degussa Corporation concerning 172.101, 173.2. ## Document text <<>> U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Ave., SE Washington, DC 20590 FEB 1 1 2009 Mr. John Foglio Manager, Hazardous Materials Transportation Safety Evonik Degussa Corporation 379 Interpace Parkway P.O. Box 677 Parsippany, NJ 07054-0677 Reference No. 08-0291 Dear Mr. Foglio: This is in response to your November 20,2008 letter concerning the most appropriate proper shipping name for a material that meets the definition of a Packing Group I1 flammable liquid (Class 3), Packing Group I1 corrosive (Class 8), and Packing Group I11 poisonous (toxic, Division 6.1) liquid under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171- 180). You state your supplier describes the material as "UN 2924, Flammable liquids, corrosive, n.0.s. (Hexamethyldisilazane), 3, 8, 6.1, PG 11." You state the Hazardous Materials Table entry for the UN 2924 description and the corresponding emergency response information do not include safety information on toxic materials. You ask if "LN 3286, Flammable liquid, toxic, corrosive, n.0.s. (Hexamethyldisilazane), 3,6.1, 8, PC 11" is the more appropriate proper shipping description for this material. If a material meets the definition of more than one hazard class and is not specifically identified by name in the Hazardous Materials Table (HMT; 5 172.101), then 5 172.101(~)(12)(iii) states the hazard class of the material must be determined using the precedence criteria specified in 5 173.2a7 and a proper shipping name must be selected, according to the methods prescribed in 9 172.101(~)(12)(ii), that most appropriately describes the material. To properly class a mixture containing hazardous components, you must analyze and test the entire mixture to determine its hazard class and, if applicable, any subsidiary hazards. Please note that a mixture may or may not exhibit the hazards of one or all of its components. It is the shipper's responsibility to properly classify a hazardous material and assign it a proper shipping name from the Hazardous Material Table (HMT; 5 172.101). See 5 173.22. Based on the information you provided about the mixture and the precedence criteria prescribed in 5 173.2a7 the Class 3-Packing Group I1 takes precedence, followed by Class 8- Packing Group 11, and then Division 6.1-Packing Group 111. In addition, this material is assigned a PG I1 in accordance with Note 1 of paragraph (b) of 5 173.2a which states the most <<>> stringent packing group assigned to any of the hazards a material exhibits will take precedence. Therefore, it is the opinion of this Office the proper shipping description "UN 2924, Flammable liquids, corrosive, n.0.s." does not accurately identify the toxic hazard of the material, and the description "UN 3286, Flammable liquid, toxic, corrosive, n.0.s. (Hexamethyldisilazane), 3, 6.1, 8, PG 11" is more appropriate. See 5 1 72.10 1 (c)(12). I hope this satisfies your request. Sincerely, Hattie L. Mitchell Chief, Regulatory Review and Reinvention Office of Hazardous Materials Standards <<>> w - I N D U S T R I E S November 20, 2008 Ob* "' EVONIK OECUIIA CORPORATION Associate Administrator for 379 lnter~ace Parkwav - ~ Hazardous Materials Safety P.O. BOX 677 Parsippany, NJ 07054-0677 Pipeline and Hazardous Materials Safety Administratio11 w . e v o n i k . c o m Attention: Office of Hazardous Materials Standards (PHH-10) Phone + 1 973-541 -8042 Fax +1 973-541-8040 Department of Transportation John.foglio@evonik.com East Building 1200 New Jersey Ave, SE. Washington, DC 20590-0001 Re: Classification Dear Mr. Edward Mazzullo, We purchase a substance and subsequently offer it for transportation. It is shipped to us as UN 2924, Flammable Liquid, Corrosive, n.o.s., 3 (8) 6.1 , PC II, (~exameth~ldisilazane). Note that 6.1 is mentioned as a subsidiary hazard. We do not agree with'the classification of our supplier since the material is toxic, (6.1, PG Ill) in addition to being flammable iiquid (3, PC I I ) and corrosive (8, PG I!). We feel that the entry UN 3286, Flammable Liquid, Toxic, Corrosive is more appropriate because this entry refers to a schedule in the E/R Guide that warns for tbxicity. The schedule for UN 2924 makes no mention aboutaioxicity. We approached our supplier and we were told that the hazard of corrosive takes precedence over toxic because class 8, PC; II is more dangerous than division 6.5, PG Ill. Therefore, thev cannot use an entry that puts the word toxic before corrosive.. We agree that corrosive PG II takes precedence over toxic, PG Ill but we think that UN 3286 can be used. We were told that they cannot not change their classification unless DOT inserts a new entry for Flammable Liquid, Cosrosive, Toxic, n.0.s. vs. the current one that puts Toxic before Corrosive. I . I . , Page 1 of 2 <<>> w I N D U S T R I E S We always like to use the same classification of the manufacturer but under the circumstances we think it is dangerous to use UN 2924 because of the lack of E/R procedures for toxicity. The manufacturer feels that nothing needs to be changed because they put a toxic label on the drums. We feel that the UN number and proper shipping name are of utmost importance when there is a spill. Should the classification for a substance which is flammable liquid in PC II, corrosive liquid, PC II and toxic liquid, PC Ill be UN 2924, Flammable Liquid, Corrosive, n.0.s. 3, (8), (6.1) PG II or UN 3286, Flammable Liquid, Toxic, Corrosive, n.o.s., PC I I ? We want to make sure that our interpretation is correct and the order of the subsidiary hazards in the proper shipping name is not as irr~portant as not mentioning one hazard (toxic) at all in the proper shipping name. We thank you in advance for your much needed assistance. Sincerely, John Foglio Manager Hazardous Materials Transportation Safety Page 2 of 2 ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `1c17af9c68d4e149984822f1d1b07af4b72a388dd0077c90b61e0b15816042f3` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-22T13:50:47.145Z - Document slug: `phmsa-interpretation-08-0291` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [ "Evonik Degussa Corporation" ], "individuals": [ "Mr. John Foglio" ], "refIds": [ "08-0291" ], "catalogDates": [ "2009-02-11" ], "catalogParts": [ 172, 173 ], "catalogRowCount": 2, "sourceRecordUrls": [ "https://www.phmsa.dot.gov/node/45631" ], "linkedAttachmentUrls": [], "unavailableResponseUrls": [], "duplicateRepresentationUrls": [], "citedSections": [ "172.101", "173.2", "173.22", "173.2a" ], "catalogPageUrls": [ "https://www.phmsa.dot.gov/regulations/title49/section/172101", "https://www.phmsa.dot.gov/regulations/title49/section/1732" ], "pdfUrls": [ "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2008/080291.pdf" ], "representations": [ { "viewUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2008/080291.pdf", "detailUrl": null, "detailHtmlPath": null, "pdfUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2008/080291.pdf", "pdfArtifactPath": "data/sources/phmsa-interpretations/08-0291-bf583e54c1.pdf", "pdfArtifactSha256": "e910ca38d24f2016589c2706a245bc24c2b97e4ca8a547e7637705158d3e6231", "extractedTextPath": "data/sources/phmsa-interpretations/08-0291-bf583e54c1.v2.txt", "extractedTextSha256": "41ae62731fe6f6f1921d86198fda22e2039a17856573f6f2b06d3f70046e463e", "pageCount": 4, "extractionVersion": 2 } ], "caveat": "Interpretations apply regulations to the facts presented and do not create independently enforceable requirements.", "jurisdiction": "US" } ```