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Interpretation Response #09-0273 ([Dow Corning Corporation] [Mr. Stephen V. Moser])

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

Interpretation Response Details

Response Publish Date:

Company Name: Dow Corning Corporation

Individual Name: Mr. Stephen V. Moser

Location State: MI Country: US

View the Interpretation Document

Response text:

March 1, 2010




Mr. Stephen V. Moser

Assistant General Counsel

Dow Corning Corporation

Midland, Michigan 48686-0994

Ref. No.: 09-0273

Dear Mr. Moser:

This responds to your letter dated November 9, 2009 regarding the proper hazard classification for Chlorosilanes products under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically, you ask whether Chlorosilanes products currently not classed as Division 4.3 (Dangerous When Wet) materials in the § 172.101 Hazardous Materials Table

(§ 172.101 HMT) meet the definition in § 173.124(c) for a Division 4.3 (Dangerous When Wet) material.

According to your letter, you are seeking reaffirmation of your understanding of a previous letter, dated March 18, 1998, from the International Standards Coordinator for Hazardous Materials Safety to Ms. Laura Neuwirth, Lathan & Watkins, that discusses subsidiary labeling requirements for materials that meet Division 4.3 criteria.

You did not provide sufficient information (e.g., hazard characteristics, material safety data sheet (MSDS)) for this Office to make a determination concerning the classification of your Chlorosilanes products. Under § 173.22 of the HMR, it is the shipper's responsibility to properly classify a hazardous material. This Office does not perform that function.

As you are aware, the § 172.101 HMT specifically lists the basic description "Trimethylchlorosilane, 3, UN 1298, II", as a Class 3 (Flammable liquid) material with a subsidiary hazard of Class 8 (Corrosive). The proper labels for a Class 3 material having a subsidiary hazard of Class 8 are the FLAMMABLE LIQUID and CORROSIVE hazard warning labels. However, it is the shipper's responsibility to determine if a material has any other subsidiary hazards that require subsidiary hazard labels or placards under the provisions of

§§ 172.402 and 172.505, respectively. Such determinations are not required to be verified by this Office. If your material meets the definition for a Division 4.3 material as specified in

§ 173.124(c), then the shipping paper must note the Division 4.3 subsidiary hazard and the

package must bear a Division 4.3 label, whether or not the Division 4.3 subsidiary hazard is indicated in the §172.101 HMT entry for the material.

I hope this information is helpful. If we can be of further assistance, please contact us.


Charles E. Betts

Chief, Standards Development

Office of Hazardous Materials Standards

172.101, 173.22, 173.124

Regulation Sections

Section Subject
172.101 Purpose and use of hazardous materials table
173.124 Class 4, Divisions 4.1, 4.2 and 4.3-Definitions
173.22 Shipper's responsibility