This document is a formal interpretation letter issued by the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA). It responds to a private party’s request for clarification about how federal hazardous materials regulations apply to radioactive materials during transportation, specifically under 49 C.F.R. Part 173.
Interpretation letters like this are part of PHMSA’s guidance system. They explain how the agency understands and applies existing regulations to real-world scenarios, such as materials generated from oil and gas operations that may contain low levels of radiation.
This document is not a law or regulation, and it does not create new legal requirements. Instead, it provides official federal guidance on how existing rules should be interpreted and enforced:
- It clarifies that federal transport rules for radioactive materials (Class 7) only apply if a material meets the regulatory definition of “radioactive material.”
- If a substance falls below specific radiation thresholds, it is not legally treated as radioactive hazardous material under federal transport law.
- It confirms that packaging and transport requirements in Part 173 do not apply unless those thresholds are exceeded.
While not binding on its own, this interpretation reflects how PHMSA is likely to enforce the law in practice and can influence compliance decisions and legal disputes.
