USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #99-0269 ([Poitevent Carrère & Denègre L.L.P.] [Mr. Stanley A. Millan])

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

Interpretation Response Details

Response Publish Date:

Company Name: Poitevent Carrère & Denègre L.L.P.

Individual Name: Mr. Stanley A. Millan

Location State: LA Country: US

View the Interpretation Document

Response text:

December 2, 1999


Mr. Stanley A. Millan                        Ref. No. 99-0269
Jones Walker Waechter
Poitevent Carrère & Denègre L.L.P.
201 St. Charles Avenue
New Orleans, LA 70170-5100

Dear Mr. Millan:

This is response to your letter dated October 1, 1999, concerning the definition of hazardous substance under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180).

Under § 171.8, a hazardous substance is defined as a material, including its mixtures and solutions, that: (1) is listed in Appendix A to § 172.101 of the HMR; (2) is in a quantity, in one package, which equals or exceeds its reportable quantity; and (3) is in a concentration by weight which equals or exceeds the concentration corresponding to the RQ of the material, as shown in the table under § 171.8.

For example, n-Butyl phthalate has an RQ of 10 pounds.  To meet the definition of a hazardous substance, the quantity of n-Butyl phthalate in each package must equal or exceed 10 pounds, and the concentration by weight must be equal to or be greater than 0.02% (200 ppm).

I hope this satisfies your request.



John A Gale
Transportation Regulations Specialist
Office of Hazardous Materials Standards


Regulation Sections

Section Subject
171.8 Definitions and abbreviations