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

Interpretation Response #09-0013R

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

Interpretation Response Details

Response Publish Date:

Company Name: Clean Harbors Environmental Services, Inc.

Individual Name: Anthony Cellucci

Location State: MA Country: US

View the Interpretation Document

Response text:

October 15, 2019

Anthony P. Cellucci
Director, Transportation Compliance
Clean Harbors Environmental Services, Inc.
42 Longwater Drive
Norwell, MA  02061-9149

Reference No. 09-0013R

Dear Mr. Cellucci:

The Pipeline and Hazardous Materials Safety Administration is clarifying this previously issued letter of interpretation based on further review. In your November 14, 2007, letter, you had requested clarification of the Hazardous Material Regulations (HMR; 49 CFR Parts 171-180) pertaining to the classification of explosives. Specifically, you requested clarification on when an approval is needed for a waste stream containing a small amount of a Class 1 (explosive) material. You also asked if there is a threshold upon which an assumption may be made by the shipper that the material meets the definition of another hazard class or does not meet the definition of a hazardous material.

Your letter provided two scenarios. In the first, a customer manufactures Trinitrotrimethylenetriamine (RDX) by incorporating the material into a solution of isopropanol and water in order to regulate the particle size. The explosive material is then removed from the isopropanol/water/RDX solution in a rotary evaporation procedure. The resultant waste material consists of a solution that contains 4.5% water, 93.7% isopropanol, 1.73% bis(2ethylhexyl) adipate (a non- DOT regulated plasticizer), .07% RDX and a non-detectable amount of cyclotetramethylenetetramine (HMX). In the second, a remediation project is conducted in which contaminated soils that contain trace amounts of RDX and/or HMX are excavated for disposal at a licensed waste management facility.

A "new explosive" is an explosive produced by a person who has not previously produced that explosive, or has previously produced that explosive but has made a change in the formulation, design, or process so as to alter any of the properties of the explosive. The term "formulation" as used in the definition of a "new explosive" applies to the entire mixture and not just the explosive components. An explosive is considered "not a new explosive" if an agency listed in paragraph (b) of § 173.56 (e.g., Explosive Test Lab) has determined and confirmed in writing to the Associate Administrator that there are no significant differences in hazard characteristics from the explosive previously approved (see § 173.56(a)).

All new compositions containing any amount of explosive material must be classed and approved by DOT, including compositions of diluted (desensitized) explosives or explosives combined or contaminated with other materials. In our original response of April 8, 2009, we stated that an approved explosive that has been mixed with non-explosive or non-hazardous materials may be considered a "new explosive" if the change in formulation increases its sensitivity toward initiation or energetic content. Following review, we wanted to clarify that determination of a "new explosive" is not limited to an increase in sensitivity nor limited to a change in formulation only, but rather any change in formulation, design, or process must be examined to determine whether the change altered any of the properties of the explosive. [Emphasis added]. This examination must be carried out by an agency listed in and in accordance with § 173.56(b) (e.g., Explosive Test Lab). The agency may either determine that the new formulation does not have significant differences in hazard characteristics and is therefore "not a new explosive" in accordance with § 173.56(a)(2) when compared to the previously approved formulation, or they may make a class recommendation as a "new explosive."

Our original response of April 8, 2009, also stated that an approved explosive that is to be discarded as a waste because it is off-spec would be a "new explosive" if the change in formulation that causes the material to be off-spec would increase the sensitivity toward initiation or energetic content of the explosive. Although this is accurate, we want to reiterate that all changes must be examined to determine whether the properties have been altered (see above for additional explanation regarding determination of "not a new explosive" or "new explosive") and that this may not be self-determined but must be determined in accordance with § 173.56(b). Further, and as detailed in our original response of April 8, 2009, if the explosives are mixed with filters, rags, dirt, or other material to be transported as waste, the waste is a "new explosive" and must be approved in accordance with § 173.56(b).

Lastly, in accordance with § 173.56(i), if experience or other data indicate that the hazard of a material or a device containing an explosive composition is greater or less than indicated according to the definition and criteria specified in §§ 173.50, 173.56 and 173.58, the Associate Administrator may specify a classification or except the material or device from the requirements of the HMR.

I hope this information is helpful. Please contact us if we can be of further assistance.


Shane C. Kelley
Standards and Rulemaking Division

173.56, 173.56(a), 173.56(b), 173.56(a)(2), 173.56(i), 173.50, 173.56, 173.58,

Regulation Sections

Section Subject
173.50 Class 1-Definitions
173.56 New explosives-definition and procedures for classification and approval
173.58 Assignment of class and division for new explosives