Transportation of non-hazardous materials containing radionuclides
Pipeline and Hazardous Materials Safety Administration · Jan 15, 2008 · Reference No. 07-0205
Interprets: 49 CFR § 171.1
Reggie’s quick take
A company asked whether the hazardous materials rules apply to shipping soil that holds naturally occurring radioactive material above the reportable quantity. Its example was soil from a cleanup site with 10 pCi/g of thorium-232, carried in a 103-ton rail car. PHMSA said yes. The total curies in that rail car exceed the thorium-232 reportable quantity of 0.001 Ci, so the soil is a hazardous substance under § 171.8 and is covered by the rules as a Class 9 material. The letter also notes that releases of this soil are subject to EPA reporting under 40 CFR 302.6(c).
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
This responds to your October 11, 2007 email requesting clarification of the applicability of hazardous substance requirements to the transportation of non-hazardous materials containing radionuclides under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically, you ask whether the HMR apply to the bulk transport of non-hazardous material containing naturally-occurring radionuclides that exceed the reportable quantity (RQ) threshold.
You indicate in your example that soil from a remediation site containing 10 pCi/g of thorium-232 is transported in a 103-ton capacity rail car and is subject to the HMR as a Class 9 hazardous substance because the total quantity in curies (Ci) in the rail car exceeds the RQ for thorium-232 (0.001 Ci).
Your understanding is correct. By definition, your example would qualify as a hazardous substance and be subject to the HMR. A hazardous substance (as defined in § 171.8) means a material, including its mixtures and solutions, that is listed in Appendix A to § 172.101 of the HMR; is in a quantity, in one package, that equals or exceeds the reportable quantity (RQ) listed in Appendix A to §172.101 of the HMR; and for radionuclides, when in a mixture or solution, conforms to paragraph 7 of Appendix A to §172.101.
The Superfund Amendments of 1986 require PHMSA to list and regulate as hazardous materials those hazardous substances listed or designated under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980. The intent of the requirement is to enable transporters of hazardous materials to identify CERCLA hazardous substances and to make the required notification if a release occurs. Additionally, based on guidance from the EPA Office of Solid Waste and Emergency Response, a release of naturally-occurring radionuclides from the transportation of soil removed from a remediation site is subject to reporting under 40 CFR 302.6(c). Please consult 40 CFR 302.6(c) for categories of releases that are exempt from the EPA notification requirements.
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.