The global chemical liability of humanity's uranium: Metrics, containment, and governance pathways

While spent nuclear fuel is managed with long-term containment strategies, depleted uranium (DU) and uranium mill tailings (UMT)—which constitute over 90 % of humanity's uranium inventory (HUI)—are generally stored with minimal durable protection. This paper reframes uranium as a planetary-scale chemo-toxic liability and introduces two intuitive, inventory-wide hazard metrics: Dilution Liability (DL)—the volume of water needed to dilute uranium below nephrotoxic thresholds—and Total Lifetime-equivalent Dose (TLD)—the number of human lifetime ingestion doses present in a given stock. DL and TLD expose the scale and persistence of uranium's hazard in simple, policy-relevant terms. A national case study of Finland illustrates how these tools support uranium-inventory liability assessments and open avenues for long-term stewardship, environmental justice, and global accountability. The paper also proposes a common exposure threshold to help unify currently siloed chemical and radiological regulatory frameworks. The analysis reveals a web of international responsibilities across the uranium value chain and proposes differentiated pathways: deep geological disposal for DU, more durable and participatory solutions for UMT, and transparent national accounting as a first step toward shared global governance. Overall, the paper translates a previously invisible, under-regulated hazard into implementable, scalable tools for planetary accountability.