Congressional hearing confronts contentious deep-sea mining issues

Several developments last month are likely to shape the future of the controversial deep-sea mining industry. A congressional hearing on the subject highlighted the widely touted promise of seabed mining and its perils.

On April 24, US president Donald J. Trump signed an executive order to expedite the review and issuing of seabed mining licenses and permits in international waters. “These [offshore] resources are key to strengthening our economy, securing our energy future, and reducing dependence on foreign suppliers for critical minerals,” the order states.

Then, on April 29, a US-based subsidiary of The Metals Company, a Canadian seabed mining firm, announced that it had submitted applications to the US National Oceanic and Atmospheric Administration (NOAA) to extract from the ocean floor critical minerals such as those used in electric vehicle batteries and renewable energy technologies. The announcement came on the same day the US House Natural Resources Subcommittee on Oversight and Investigations held a hearing to explore the potential of deep-sea mining.

The Metals Company made three applications—one for commercial mining and two for exploratory mining. All sites are located in the Clarion-Clipperton Zone, an area in the central Pacific Ocean that’s beyond US jurisdiction and rich in potato-shaped rocks called polymetallic nodules.

If NOAA approves the applications, the move would be the first to bypass the International Seabed Authority (ISA)—an intergovernmental body in charge of regulating seabed mining in international waters, which begin about 370 km off a nation’s coastline. The ISA, which became operational in 1996, consists of 169 member states and the European Union; the US isn’t a member. Many nations have already protested The Metals Company’s earlier announcement in March of its plan to approach the US for permits.

The ISA’s powers conflict with the Deep Seabed Hard Mineral Resources Act, which Congress passed in 1980 and forms the basis for the executive order. The act allows US-based companies or citizens to explore for or recover seabed minerals in international waters. In a March 2025 statement after The Metals Company announced its plans to submit an application to NOAA to begin mining, ISA secretary general Leticia Carvalho said that “all exploration and exploitation activities in the area must be carried out under the authority’s control.”

The ISA has not finalized regulations on deep-sea mining, including those that allow for environmental protection from mining’s harmful effects on marine biodiversity. So far, the intergovernmental body has missed deadlines to finalize the rules.

During the April 29 oversight hearing, some members of the subcommittee expressed concerns about Trump’s seabed mining order and questioned the need for such mining.

Rep. Jared Huffman (D-CA) called deep-sea mining a “dirty, destructive, and unproven industry.” He said it won’t solve the country’s needs for critical minerals to advance the transition to clean energy but is likely to “create a whole new class of problems.” Hoffman was referring to analyses suggesting that seabed mining might cause irreversible harm to marine biodiversity and to concerns from Pacific Islands’ Indigenous leaders about mining-related damage that could affect the oceans they rely on and consider culturally significant.

Rep. Maxine Dexter (D-OR) called seabed mining a “high-risk, low-reward endeavor.” She questioned the industry’s financial viability given the high costs of operation, significant technological hurdles involved in mining in the deep ocean, and a volatile minerals market. Dexter added that it was “unfortunate” that Trump issued the executive order “knowing that we had this hearing forthcoming, showing his disregard for transparency and public input.”

But Rep. Paul Gosar (R-AZ) reminded his subcommittee colleagues that China has dominated global critical mineral supply chains. Two witnesses at the hearing—Gerard Barron, CEO of The Metals Company, and Oliver Gunasekara, CEO of Impossible Metals, a California-based deep-sea mining firm—argued that seabed mining is essential if the US is to reduce its dependence on other countries for critical minerals. Gunasekara spoke of the need to first harness “the enormous reserve of nodules” in US waters, a step that would not conflict with international law.

Both he and Barron touted seabed mining as a vital alternative to land-based mining. But some experts have argued that it’s not an either-or situation and that extraction of minerals from the deep sea is unlikely to replace terrestrial mining.

Another witness, Duncan Currie, a legal adviser to the Deep Sea Conservation Coalition, noted that the demand for the nickel and cobalt found in nodules is declining for electric vehicle batteries as the industry moves to batteries made with lithium iron phosphate. He added that 32 of ISA’s members have called for a pause or moratorium on deep-sea mining given its unknown environmental risks.

But Thomas Peacock, a professor of mechanical engineering at the Massachusetts Institute of Technology who studies the impacts of seabed mining, said that the environmental consequences of extracting nodules “may not be as severe as speculated.”

Peacock advocated a step-by-step approach that would entail gradually scaling up commercial mining operations with robust regulations in place. It would also include regular environmental monitoring to help inform officials if mining operations must be stopped or amended.