Interpretation Response #08-0291
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Mr. John Foglio
Manager, Hazardous Materials
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||Purpose and use of hazardous materials table|