Highlights

• Rare earth processing concentrates uranium and thorium into TENORM residues, triggering complex federal and state radiological compliance requirements that are critical to project bankability and financing confidence.
• Regulatory jurisdiction hinges on whether materials exceed 0.05% uranium/thorium thresholds, with oversight split between NRC/Agreement States for source material and state TENORM programs for processing residues.
• Successful compliance requires six core elements: radiological characterization, licensing determination, pathway control, engineered storage, closure planning with financial assurance, and worker protection programs.

---

Rare earth element (REE) ores—especially monazite and xenotime—often contain measurable uranium and thorium. During beneficiation and separation, these radionuclides can become concentrated in sludges, tailings, scales, and process residues. The result is Technologically Enhanced Naturally Occurring Radioactive Material (TENORM).

The U.S. Environmental Protection Agency (opens in a new tab) defines TENORM (opens in a new tab) as naturally occurring radioactive materials whose concentrations or exposure pathways are increased by industrial activity. In REE projects, this means radiological compliance is not limited to “ore grade.” Dust control, wastewater treatment, residue stability, radon management, and long-term tailings stewardship become central to bankability.

The Regulatory Map: Source Material vs. TENORM

The pivotal legal question is jurisdiction. Under 10 CFR Part 40 (opens in a new tab), uranium and thorium are regulated as “source material,” including ores containing ≥0.05% by weight uranium and/or thorium. A frequently cited exemption applies to certain finished rare earth products containing ≤0.25% by weight uranium/thorium. However, that exemption does not automatically resolve compliance if radionuclides are concentrated into waste streams.

If licensing is triggered, oversight falls to the U.S. Nuclear Regulatory Commission (opens in a new tab) or to an NRC “Agreement State,” which has assumed authority for materials licensing and inspection.

For many REE operations not extracting uranium primarily for its source-material value, radiological residues are treated as TENORM and regulated primarily at the state level. A briefing from Pacific Northwest National Laboratory (opens in a new tab) has warned that radiological issues—if deferred—can delay projects even when broader permitting reform accelerates NEPA timelines.

A critical boundary issue: EPA’s 40 CFR Part 192 (opens in a new tab) standards apply to uranium and thorium extraction facilities and their 11e.(2) mill tailings from ore processed primarily for source material. Conventional open-pit or underground mines not primarily extracting uranium typically fall outside that specific regime—but remain subject to state TENORM programs and conventional environmental permitting.

Two additional overlays:

• The RCRA mining exclusion (40 CFR 261.4(b)(7), the“Bevill Amendment” (opens in a new tab)) may apply to certain mining wastes—but does not eliminate radiological oversight.
• DOT Class 7 transport rules (49 CFR) apply to radioactive shipments and operate “in addition to” NRC packaging requirements under 10 CFR Part 71.

A Bankable Compliance Workflow

From a financing and investor perspective, the key risk is misapplying the “0.25% product exemption” as a blanket solution. Once uranium or thorium concentrates into residues, engineered management—not product concentration—determines regulatory exposure.

U.S. REE Radiological Compliance Workflow Framework

	Compliance Element	Core Activities	Primary Regulators/Standards	Key Risk if Neglected
1	Radiological Characterization	∙ Gamma surveys and lab isotopic assays (U, Th, progeny) ∙ Sampling of ore, concentrates, tailings, scale, dust, wastewater ∙ Radionuclide mass balance ∙ QA/QC protocols and chain-of-custody documentation	U.S. Environmental Protection Agency (TENORM guidance) State TENORM programs 10 CFR Part 40 thresholds	Misclassification of material; unexpected licensing trigger; investor diligence failure
2	Licensing Determination	∙ Evaluate ≥0.05% source material threshold ∙ Assess applicability of ≤0.25% product exemption ∙ Engage regulator early for jurisdictional clarity	U.S. Nuclear Regulatory Commission or NRC Agreement States 10 CFR Part 40	Project delays due to late licensing determination; enforcement exposure
3	Pathway Control	∙ Dust suppression and air monitoring ∙ Effluent treatment and discharge compliance ∙ Gamma dose rate monitoring ∙ Radon daughter sampling (underground where applicable)	State environmental agencies Mine Safety and Health Administration (underground mines) OSHA ionizing radiation standards	Worker overexposure; community concern; permit suspension
4	Engineered Storage & Disposal	∙ Tailings facility design (stability, liners, seepage control) ∙ Encapsulation or segregation of high-Th residues ∙ Environmental monitoring systems ∙ Long-term integrity modeling	State TENORM programs RCRA mining exclusion considerations (40 CFR 261.4(b)(7)) EPA oversight where applicable	Capital market resistance; closure liabilities; groundwater contamination
5	Closure Planning & Financial Assurance	∙ Radiological site model at closure ∙ Post-closure monitoring plan ∙ Financial assurance instruments (bonding, trust funds) ∙ Stewardship obligations	State mining agencies EPA (where federal lands involved) BLM (if applicable)	Unfunded long-term liability; permit revocation; inability to obtain financing
6.	Worker Protection Compliance	∙ Personal dosimetry programs ∙ Radon daughter sampling (WLM tracking) ∙ ALARA-based safety program ∙ Radiation Safety Officer oversight ∙ Recordkeeping & training	Mine Safety and Health Administration OSHA NRC or Agreement State (if licensed)	Enforcement penalties; litigation exposure; rep

For underground operations, the Mine Safety and Health Administration regulates exposure to radon daughters and gamma radiation in metal and nonmetal mines, with periodic sampling requirements tied to working levels.

Thorium’s “Nuclear Potential” and Regulatory Sensitivity

Thorium-232 is not fissile—but it is fertile. When irradiated in a reactor, it can convert to uranium-233, which is legally defined as “special nuclear material.” This connection elevates regulatory sensitivity.

Projects that stockpile or market thorium-bearing concentrates—even as byproducts—should anticipate scrutiny around:

• NRC licensing determinations
• DOT transport classification
• Potential export controls under nuclear materials regulations

Even if the primary product is a rare earth oxide, regulators will evaluate whether byproduct handling implicates source material or special nuclear material frameworks.

Expert Firms Supporting REE Compliance

Navigating this landscape requires interdisciplinary engineering, radiological science, and permitting expertise. A few companies in the space are listed below.

SRK Consulting (opens in a new tab)

A global mining advisory firm offering environmental permitting, mine waste, and tailings storage design. Particularly valuable where TENORM characterization must translate into engineered containment and closure strategies.

WSP (opens in a new tab)

Provides integrated mine waste and tailings lifecycle management, including geochemical characterization and regulatory documentation. Well-suited for documentation-intensive state TENORM regimes.

Tetra Tech (opens in a new tab)

Strong in NEPA integration, permitting strategy, and environmental impact assessment. Useful where radiological considerations must be embedded into federal review processes.

RSO Services (opens in a new tab)

Offers Radiation Safety Officer training, record audits, and regulatory program support. Particularly helpful in building auditable radiation safety programs and transport compliance systems.

Bottom Line: In U.S. rare earth ventures, radiological compliance is not a niche technical footnote—it is a capital markets issue. The decisive factors are early characterization, correct jurisdictional determination, engineered residue management, and transparent long-term stewardship planning. Projects that treat radiation as a peripheral issue often discover it is central to the timeline, permitting durability, and financing confidence.