Deep Atlantic finds reveal 200,000 leaking radioactive waste barrels on the seafloor

An international, French-led expedition descended about 15,400 feet into the Northeast Atlantic to directly observe more than 200,000 barrels of largely corroded, low‑level radioactive waste dumped in the latter half of the 20th century, with material spilling onto the seafloor. On-site measurements detected radionuclides such as cobalt-60, niobium-94, cesium-137 and americium-241 above background levels, though scientists caution this is not yet a final ecological verdict. A 2025 mission mapped thousands of barrels with the Ulyx robot to guide 2026 close‑range dives, which also noted deep‑sea life colonizing the waste sites. Researchers say more laboratory work is needed to determine exact concentrations, how radionuclides move through sediment and water, and whether deep‑sea organisms are absorbing them, while international efforts (OSPAR) continue to study historic dumping practices and their ecological implications.