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Interpretation Response #08-0291 ([Evonik Degussa Corporation] [Mr. John Foglio])

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Evonik Degussa Corporation

Individual Name: Mr. John Foglio

Location State: NJ Country: US

View the Interpretation Document

Response text:

February 11, 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 II flammable liquid (Class 3), Packing Group II corrosive (Class 8), and Packing Group III 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.o.s. (Hexamethyldisilazane), 3, 8, 6.1, PG II." 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 "UN 3286, Flammable liquid, toxic, corrosive, n.o.s. (Hexamethyldisilazane), 3, 6.1, 8, PG II" 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; § 172.101), then § 172.101(c)(12)(iii) states the hazard class of the material must be determined using the precedence criteria specified in § 173.2a, and a proper shipping name must be selected, according to the methods prescribed in § 172.101(c)(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;

§ 172.101). See § 173.22.

Based on the information you provided about the mixture and the precedence criteria prescribed in § 173.2a, the Class 3-Packing Group II takes precedence, followed by Class 8-Packing Group II, and then Division 6.1-Packing Group III. In addition, this material is assigned a PG II in accordance with Note 1 of paragraph (b) of § 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.o.s." does not accurately identify the toxic hazard of the material, and the description "UN 3286, Flammable liquid, toxic, corrosive, n.o.s. (Hexamethyldisilazane), 3, 6.1, 8, PG II" is more appropriate. See § 172.101(c)(12).

I hope this satisfies your request.


Hattie L. Mitchell

Chief, Regulatory Review and Reinvention

Office of Hazardous Materials Standards

172.101, 173.2

Regulation Sections

Section Subject
172.101 Purpose and use of hazardous materials table
173.2 Hazardous materials classes and index to hazard class definitions