Photo by NOAA
The Trump administration has moved a step closer to opening up a large area of Pacific seafloor to commercial mining, in a plan that has drawn sharp opposition from the US territories most directly affected and from environmental groups warning of serious harm to marine ecosystems.
The proposal
The Marine Mineral Administration (MMA), an agency under the US Department of the Interior, has published a Proposed Leasing Notice covering federal waters off the Commonwealth of the Northern Mariana Islands (CNMI), setting out proposed terms for a possible commercial mineral lease sale across 28 million hectares of seafloor off the coast of the Northern Mariana Islands and Guam. The leases would allow companies to explore for, and potentially extract, deposits of critical minerals known as polymetallic nodules, which contain manganese, nickel, cobalt and copper used in batteries, electronics and defence technologies. The MMA has also completed an accompanying environmental assessment.
MMA acting director Matt Giacona set out the rationale behind the move, saying: “Critical minerals are essential to America’s national security, economic strength and resource sovereignty.” The plan follows Donald Trump’s executive order of April 2025, “Unleashing America’s Offshore Critical Minerals and Resources”, and an earlier request for information that drew more than 65,000 public submissions.
Territorial governments push back
The Northern Mariana Islands is a self-governing US commonwealth, while Guam is an unincorporated US territory; both would sit adjacent to the proposed lease area. Northern Marianas Governor David Apatang has responded with pointed caution. Acknowledging the strategic importance of critical minerals, he said his government would approach the proposal “with extreme caution,” adding that it was necessary that “no activity, survey or otherwise, takes place without rigorous scientific baseline studies, complete transparency, and explicit protections for our marine resources.” His administration, he said, would “thoroughly examine the proposed terms over the next 60 days to ensure that the ecological integrity of our waters and the long-term wellbeing of the [Northern Marianas] are fully safeguarded.”
A parallel legal challenge
The Mariana Islands proposal follows a separate but related dispute over a mining lease process near American Samoa. On 19 August, environmental groups in American Samoa and Hawaii launched legal proceedings in a Hawaii court against the federal government, seeking to halt the proposed auction of seafloor permits around American Samoa. The plaintiffs, Fa’asao Ameika Samoa and the Conservation Council for Hawaii, argue that federal agencies failed to properly evaluate the potential damage to marine ecosystems, warning in their complaint that extraction machinery “can destroy nearly all life in its path” and that mining activity “stirs up sediments that can introduce toxic substances into the food web and smother seafloor ecosystems.” The complaint adds that even exploratory surveying “introduces extremely loud noise into the marine environment that can harm marine mammals and other wildlife.” Commercial deep-sea mining in the Pacific could begin as early as 2027, notwithstanding the continued absence of an agreed international regulatory framework for the practice.
A contested frontier
The push into Pacific waters forms part of a broader administration strategy to secure domestic supplies of critical minerals amid competition with China, but it has consistently run into resistance from the communities closest to the proposed mining zones. Residents of Guam raised similar concerns earlier this year over a related proposal to open waters further west to mining, with local advocates emphasising the cultural and ecological significance of the ocean to Indigenous Chamorro communities. Environmental organisations, including Greenpeace, have continued to argue that established marine sanctuaries deliver proven benefits for biodiversity, coastal economies and fisheries productivity that outweigh the case for seabed extraction.
The debate also sits within a wider, unresolved international question: no comprehensive global framework yet governs deep sea mining in areas beyond national jurisdiction, and the International Seabed Authority’s own negotiations over a mining code remain ongoing. The Pacific leasing proposals now advancing in US waters are likely to sharpen that debate, both for other coastal and island states weighing similar decisions and for the conservation and fisheries organisations that follow seabed governance closely.