Deep-Sea Nodules Pose Minimal Radiation Risk, New Study Finds

A recent peer-reviewed study published in Nature Scientific Reports has concluded that polymetallic nodules, targeted for deep-sea mining, do not present a significant radiation risk to humans under standard operating conditions. The findings directly address and clarify previous concerns, asserting that potential exposure levels are well within occupational safety limits.

Gerard Barron, CEO of The Metals Company (TMC), highlighted the study's importance, stating on social media, > "Last month, @Nature published a peer-reviewed study confirming what many of us already knew: polymetallic nodules do not pose a radiation risk to humans." He further noted that the previous claim took "a few years to unwind," suggesting it was based on misinterpretations.

The new research by Lüttke et al. (2025) effectively rebuts a 2023 study by Volz et al., which had raised alarms by suggesting nodule radioactivity exceeded exemption levels by up to 1,000 times. Lüttke et al. clarified that Volz's analysis incorrectly applied regulatory standards designed for artificial radioactive materials, rather than the less stringent thresholds for Naturally Occurring Radioactive Materials (NORM) like polymetallic nodules. Their comprehensive assessment indicates that with appropriate safety measures and ventilation, worker exposure during transport and processing would remain below 2 mSv/a, comparable to other NORM-associated industries.

Barron also drew a parallel to another emerging controversy, remarking, > "No doubt the fallacy that is 'Dark Oxygen' will have a similar fate given time." This refers to a July 2024 Nature Geoscience paper by Sweetman et al., which proposed that nodules generate oxygen in the deep sea, a claim that environmental groups cited as a reason to halt deep-sea mining. However, TMC, a partial funder of that research, issued a rebuttal, alleging methodological flaws, omitted data, and selective reporting in the "Dark Oxygen" study.

The deep-sea mining industry, led by companies like TMC, seeks to extract critical metals such as nickel, cobalt, and manganese from these nodules, essential for electric vehicle batteries and renewable energy technologies. Despite the scientific clarification on radiation and the ongoing debate over "Dark Oxygen," the sector continues to face significant environmental scrutiny and regulatory challenges, including recent moves by TMC USA to secure permits under U.S. jurisdiction, which has drawn criticism from the International Seabed Authority (ISA) and other nations.