Interpretation Response #25-0013

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

Interpretation Response Details

Response Publish Date: 09/23/2025

Company Name: KVAC Environmental

Individual Name: Kyle McLaughlin

Location State: CA Country: US

View the Interpretation Document

Response text:

September 23, 2025

Mr. Kyle McLaughlin
Compliance Manager
KVAC Environmental
PO Box 1505
Rancho Cucamonga, CA  91729

Reference No. 25-0013

Dear Mr. McLaughlin:

This letter is in response to your January 2, 2025 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to hazardous substance determinations and shipping descriptions.

We have paraphrased and answered your questions as follows:

Q1. How can an offeror of hazardous materials reconcile differences between Appendix A to the § 172.101 table and 40 CFR § 302.4 when determining the reportable quantity of a hazardous substance, specifically when dealing with materials listed due to constituents vs. hazard characteristics?

A1. The Department of Transportation (DOT) is required by the Superfund Amendments and Reauthorization Act of 1986 to regulate as hazardous materials those materials designated as hazardous substances under Section 101(14) of the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA). However, the Department was not given authority to determine what is or is not a hazardous substance or the appropriate reportable quantity (RQ) for materials designated as hazardous substances. This authority is vested in the Environmental Protection Agency (EPA). The list of hazardous substances, designated under Section 101(14) of CERCLA, has been prescribed by the EPA under 40 CFR § 302.4. DOT's corresponding list of hazardous substances and reportable quantities is found in Appendix A to § 172.101 of the HMR. As stated in the previous Letter of Interpretation you referenced (Reference No. 04-0182), when the specific constituent of the hazardous waste and its respective concentration is known, the RQ for the constituent should be used when determining whether a reportable quantity has been met.

Q2. Must similar containers of a material be listed separately on a shipping paper when only some exceed the reportable quantity?

A2. No. Packages may be described under one line entry on a shipping paper using the "RQ" designator provided some of the packages contain a reportable quantity.
In addition, please note on July 1, 2025, PHMSA published a notice of proposed rulemaking titled "Hazardous Materials: Remove Redundant List of U.S. EPA CERCLA Hazardous Substances" under Docket HM-268E. PHMSA proposes to revise the HMR to remove redundant pages contained in an Appendix that repeats references already listed in EPA regulations. If adopted, HM-268E would direct readers to the 40 CFR § 302.4 list to determine whether a material meets or exceeds the RQ.

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

Sincerely,

Alexander Wolcott
Acting Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

40 CFR § 302.4, § 172.101

Regulation Sections