This article contains a transcript of an important USDOT/PHMSA interpretation letter.  Unfortunately, since it is greater than ten years old, it no longer is available on the Administrations website:  HazMat Interpretations.  If you wish for an original of the letter you should contact the Hazardous Materials Information Center.

June 4, 1998

Mr. Joseph Grebe
Manager, Testing and Technical Service
Greif Bros. Corporation
1201-A South Houk Road
Delaware, Ohio 43015

Dear Mr. Grebe:

This is in response to your letter dated March 20, 1998, regarding the package marking requirements in 49 CFR 178.503(a)(4)(ii) under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180).  Specifically, you ask us to define the terms “net mass” and “gross mass.”

The term gross mass is defined in § 171.8 as “the weight of a packaging plus the weight of its contents.”  The term “net mass” means the weight of the contents in a packaging.  The difference between the two terms is the fact that you include the weight of the packaging in determining its gross mass but you do not include the weight of the packaging when determining its net mass.  Therefore, a steel open head drum that weighs 35 kilograms and has a maximum net mass of 400 kilograms would be correctly marked as “1A2/X435/S…” in accordance with § 178.503(a)(4)(ii).

I hope this satisfies your request.

Sincerely,

Delmer F. Billings
Chief, Standards Development
Office of Hazardous Materials Standards