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Interpretation Response #23-0019

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

Interpretation Response Details

Response Publish Date:

Company Name: AET Environmental, Inc.

Individual Name: Frank Virginia

Location State: CO Country: US

View the Interpretation Document

Response text:

May 16, 2023

Frank Virginia
AET Environmental, Inc.
14 Lakeside Lane
Denver, CO  80212

Reference No. 23-0019

Dear Mr. Virginia:

This letter is in response to your March 6, 2023, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to waste streams containing trace amounts of explosive hazardous material. You state that your firm manages hazardous and non-hazardous waste for waste generators, and you are currently working with a DoD installation in Colorado named Pueblo Chemical Depot ("the depot"). You state that the depot has contamination of various constituents of concern throughout the facility where a specific area was identified as being in contact with explosive nitro-aromatic compounds (e.g., TNT, Dinitrotoluene, RDX, etc.). You state that these compounds have contaminated the groundwater and you state that analysis of the post treatment groundwater samples display traces of certain explosive compounds at approximately 0.053 µg/l. You ask questions regarding the applicability of the Pipeline and Hazardous Materials Safety Administration (PHMSA) explosive approval process for waste generated with trace amounts of these constituents of concern. We have paraphrased and answered your questions as follows:

Q1. You ask whether any debris (e.g., personal protective equipment (PPE)) that may have been exposed to waste streams containing trace amounts of explosive compounds must have an explosives examination report submitted to PHMSA for review under the explosive approval process.

A1. The answer is yes. Waste material that is exposed to and contaminated with explosive compounds is considered a "new explosive." 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 to alter any of the properties of the explosive (see § 173.56). The term "formulation"—as used in the definition of a new explosive—applies to the entire mixture and not just the explosive components. Any changes must be examined to determine whether the properties have been altered and this may not be self-determined but must be determined in accordance with § 173.56(b). If the explosive compounds are mixed with filters, rags, dirt, or other material (e.g., diluted with contaminated water or other solvents), it is considered a "new explosive" and must be approved in accordance with § 173.56(b).

However, it is the shipper's responsibility to determine whether a specific piece of waste material generated from the site is contaminated with explosive residue. Please note, if further process to decontaminate or neutralize contaminated PPE before declaring it as waste or if further sampling indicates there is no longer detectable explosive content, it would be possible to determine the PPE is no longer an explosive hazardous material.

Q2. You believe that the contaminated water would be considered non-hazardous waste based on the trace amount of explosive compound identified in the groundwater and you ask whether the HMR has allowances for a de minimus quantity exception for explosive material. You also seek confirmation that assigning a non-regulated hazardous material description for the material is appropriate and would not warrant submission and review in accordance with the requirements found in § 173.56(b).

A2. The answer is no. All compositions containing any amount of explosive material—including compositions of diluted (desensitized) explosives or explosives combined or contaminated with other materials—meet the definition of a new explosive and must be classified and approved by PHMSA. However, this process may result in a determination that the material is not an explosive and thus not regulated.

Please note that 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 definitions 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.


Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

173.50, 173.56, 173.56(b), 173.56(i), 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