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Interpretation Response #09-0044 ([Restek Corporation] [Mr. Erik Perrin])

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

Interpretation Response Details

Response Publish Date:

Company Name: Restek Corporation

Individual Name: Mr. Erik Perrin

Location State: PA Country: US

View the Interpretation Document

Response text:

January 28, 2010




Mr. Erik Perrin, CSP

EHS Manager

Restek Corporation

110 Benner Circle

Bellefonte, PA 16823

Ref. No. 09-0044

Dear Mr. Perrin:

This responds to your letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) as applicable to the approval of desensitized explosives. You ask whether a change of diluent meeting the same hazard class and mass would be authorized without further examination. An example you cite in your letter is a previously examined, classed and approved desensitized explosive mixture containing 1% RDX and 99% acetone. Because the mixture exhibits characteristics of the solvent and not the explosive substance when examined and tested, you ask if an alternative diluent of the same hazard class, packing group and concentration, such as methanol, could be substituted for the acetone without obtaining approval from the Associate Administrator.

As specified in § 173.124(a), unless the mixture is specifically listed by name in the § 172.101 Hazardous Materials Table (HMT), all desensitized explosive mixtures are assigned a shipping name and hazard class by the Associate Administrator under the provisions of either a special permit or approval. Furthermore, most desensitized explosive mixtures specifically listed by name in the HMT also require approval before they may be offered for transportation. Thus, written approval must be issued by the Associate Administrator if an alteration is made to any constituent within a desensitized explosive mixture unless the alteration is specifically listed by name in the HMT or is authorized in an assigned § 172.102 special provision.

I hope this information is helpful. Please contact this office if you have additional questions.


Hattie L. Mitchell

Chief, Regulatory Review and Reinvention

Office of Hazardous Materials Standards

173.124(a), 172.101 and 172.102

Regulation Sections

Section Subject
173.124 Class 4, Divisions 4.1, 4.2 and 4.3-Definitions