Contents

• Introduction
• Background on Seabed Mining
• Regulations for Deep-Seabed Mining in Areas Beyond National Jurisdiction
• United Nations Convention on the Law of the Sea and the 1994 Agreement
• International Seabed Authority
• The London Convention
• Deep Seabed Hard Mineral Resources Act and Other Applicable U.S. Laws
• Potential Marine Environmental Impacts of Seabed Mining
• Issues for Congress
• U.S. Importation of Land-Based Minerals and Seabed Mining Exploration Efforts by Selected Foreign Governments
• U.S. Ratification of United Nations Convention on the Law of the Sea
• Deep-Seabed Mining Activities in Areas Beyond National Jurisdiction
• International Seabed Authority Decisionmaking
• U.S. Federal Research to Study Seabed Mining Impacts and Associated Mining Technologies

Summary

Some scientists estimate that certain mineral deposits, including those containing critical minerals, are more abundant on the seafloor than on land. This estimate, coupled with the demand for critical minerals for rapid deployment of energy transition technologies, has increased interest in the recovery of minerals from areas beyond national jurisdiction (ABNJ). Minerals may be extracted through seabed mining, a process that involves recovering minerals from the seafloor. Although some entities hold contracts to explore the seafloor for potential commercial recovery, deep-seabed mining (i.e., mining activities taking place at water depths greater than 200 meters) in ABNJ has yet to occur. On April 24, 2025, as part of a broader national effort to secure reliable supplies for critical minerals, the Trump Administration issued an executive order titled "Unleashing America's Offshore Critical Minerals and Resources." The potential of seabed mining in ABNJ raises several issues for Congress given the United States' demand for critical minerals and concerns about potential environmental impacts.

International and U.S. Context for Seabed Mining in ABNJ

The International Seabed Authority (ISA), established under the 1982 United Nations Convention on the Law of the Sea (UNCLOS), is an autonomous organization that regulates parties to UNCLOS conducting mineral-related activities in ABNJ. The ISA can issue contracts for exploration and exploitation of seabed mineral resources to parties to UNCLOS. In 2021, the Republic of Nauru, a small island country northeast of Australia, notified the ISA of its sponsorship of Nauru Ocean Resources and its intention to recover minerals from an ABNJ in the Pacific Ocean. Nauru's action triggered a provision that required the ISA to establish by summer 2023 a mining code that would allow for deep-seabed mining. At the close of the ISA's March 2025 session, the ISA had not finalized its mining code.

The United States has not ratified UNCLOS and therefore cannot sponsor companies seeking ISA contracts. However, the Deep Seabed Hard Mineral Resources Act (DSHMRA; P.L. 96-283), signed into law in 1980 prior to the establishment of the ISA, authorized the National Oceanic and Atmospheric Administration (NOAA) to regulate deep-seabed mining activities (exploration and commercial recovery) of U.S. citizens in ABNJ. To date, NOAA has issued licenses to U.S.-based companies to explore the seafloor in ABNJ; it has not received applications for commercial recovery permits.

Issues for Congress

Sourcing minerals from the deep sea may limit U.S. dependency on importing land-based minerals and reduce potential supply disruptions. Unless the United States either ratifies UNCLOS, which would allow it to seek ISA contracts, or unilaterally authorizes deep-seabed mining under DSHMRA, U.S. companies may not have a clear U.S. avenue to pursue seabed mining activities in ABNJ. The Trump Administration has taken steps to pursue seabed mineral resources, including in ABNJ. The "Unleashing America's Offshore Critical Minerals and Resources" executive order directs NOAA to "expedite the process for reviewing and issuing seabed mineral exploration licenses and commercial recovery permits" in ABNJ under DSHMRA. Congress may consider any potential geopolitical consequences of NOAA issuing commercial recovery permits outside the ISA framework.

The April 24, 2025, executive order also made it the policy of the United States to "support allies and partners interested in developing seabed minerals responsibly in areas within their national jurisdictions," among other U.S. policies. In the 118^th Congress, some Members of Congress considered legislation related to sourcing seabed minerals from allied countries and developing infrastructure to process and refine those minerals domestically. In the 119^th Congress, S. 429 would attempt to diversify U.S. critical mineral supply chains through partnerships with countries that hold certain trade agreements with the United States.

Concerns associated with seabed mining include habitat disturbance and biodiversity loss. Congress may seek to improve understanding of the potential environmental impacts associated with seabed mining. In the 119^th Congress, H.R. 664 would authorize NOAA to "conduct a comprehensive study of the environmental impacts of mining activities on the deep seabed." H.R. 663 would direct the President to place a moratorium on deep-seabed mining.

Introduction

Interest in mining the seabed in areas beyond national jurisdiction (ABNJ) for deposits that contain valuable minerals, such as critical minerals, has grown in recent years for a few reasons.¹ First, increased resources and improved technologies dedicated to the exploration and mapping of the deep sea have advanced knowledge of seafloor deposits that contain minerals of interest.² Second, the development of technologies for systems to collect seabed minerals from the deep ocean and deliver them to ships or surface-based mining platforms has made mining the seafloor more technologically possible and potentially economically feasible.³ Third, some seabed deposits could present an alternative source of some minerals used in energy transition technologies that otherwise may rely on terrestrial minerals sourced in certain countries of concern.⁴ On April 24, 2025, President Trump issued an executive order titled "Unleashing America's Offshore Critical Minerals and Resources," which made it the priority of the United States to "rapidly develop ... domestic capabilities for the exploration, characterization, collection, and processing of seabed mineral resources."⁵

Different types of energy transition technologies rely on elements found in both terrestrial deposits and seafloor deposits (e.g., cobalt, copper, manganese, nickel).⁶ Some scientists estimate these minerals of interest are more abundant in seafloor deposits than in land deposits.⁷ For example, some batteries—including those that power electric vehicles—commonly use nickel, cobalt, and manganese.⁸ Critical minerals used in the magnets of wind turbines, the motors of electric vehicles, and stationary energy storage also occur in seafloor deposits.

This report focuses on deep-seabed mining activities that could take place in ABNJ (Figure 1).⁹ The report outlines the history of international agreements that establish guidelines and standards for deep-seabed mining activities and provide protection to the marine environment in ABNJ. It also outlines domestic regulations for U.S. interests pursuing seabed-mining activities in ABNJ. The report then discusses potential seabed mining impacts to ocean ecosystems. Finally, this report discusses issues for Congress, including U.S. participation in international agreements regarding deep-seabed mining, possible tradeoffs about domestic versus foreign supplied minerals, the potential for domestic processing of seabed minerals to bolster U.S. critical mineral supply chains, research to improve knowledge of environmental baseline data for deep-sea habitats, and calls for a moratorium on deep-seabed mining. For information about seabed mining activities within U.S. waters, see CRS Report R48302, Critical Minerals on the U.S. Outer Continental Shelf: The Bureau of Ocean Energy Management's Role and Issues for Congress, by Caitlin Keating-Bitonti and Laura B. Comay.

Figure 1. Illustration of High Seas and Exclusive Economic Zone Boundaries High seas apply to areas beyond national jurisdiction (ABNJ)

Source: Illustration created by CRS using the Sovereign Limits database (sovereignlimits.com). Data are updated quarterly by the Sovereign Limits, and data used for this illustration were most recently updated on October 1, 2022. Notes: Figure is an illustration and is not for official purposes of identifying ABNJs, exclusive economic zones (EEZs), or territorial sea limits. Boundaries of coastal countries' national jurisdictions (i.e., EEZs) are illustrated in light blue. Areas beyond national jurisdiction (i.e., the high seas) are illustrated in dark blue. As defined in the United Nations Convention on the Law of the Sea (UNCLOS), the territorial sea extends up to 12 nautical miles; the EEZ extends up to 200 nautical miles from the baseline of low sea level (usually near the coastline); and the high seas apply to "all parts of the sea that are not included in the [EEZ], in the territorial sea or in the internal waters of a State, or in the archipelagic waters of an archipelagic State" (see, UNCLOS Articles 3, 57, and 86). Peru claims a single maritime zone of 200 nautical miles, which it refers to as a maritime domain, not an EEZ; for the purposes of this figure, Peru is shown with an EEZ. Antarctica does not have a territorial sea or an EEZ because it is not a sovereign nation and its governance is carried by the Consultative Nations of the Antarctic Treaty.

Background on Seabed Mining

Seabed mining is a process of extracting sediment and mineral resources from the seafloor. In general, water depths less than 200 meters occur within nations' exclusive economic zones (EEZs), to which a coastal nation may claim sovereign rights for the purpose of exploring and exploiting the natural resources of its continental shelf.¹⁰ Seabed mining activities occurring within a nation's EEZ are regulated by that nation's domestic law.¹¹ In the United States, the seaward boundary of coastal states is generally three nautical miles offshore,¹² and certain states and territories prohibit seabed mining within their waters (e.g., American Samoa, California, Hawaii, Oregon, Washington).¹³ An emerging subset of seabed mining is deep-seabed mining, or deep-sea mining, which occurs at water depths of 200 meters or greater.¹⁴ Water depths greater than 200 meters generally occur in areas beyond the EEZ. This report focuses on seabed minerals found beyond the outer continental shelf in ABNJ.

Deep-seabed mining was first explored in the 1960s, with commercial test mining for metal-rich nodules on the seabed starting in the 1970s.¹⁵ In 1994, the International Seabed Authority (ISA) was created under the United Nations (UN) Convention on the Law of the Sea as an autonomous organization to regulate and control deep-seabed mining activities taking place in ABNJ.¹⁶ The ISA can issue exploration and exploitation (i.e., commercial recovery) contracts for three types of deep-seabed mineral deposits (Table 1).¹⁷ The technologies and machinery to extract raw seabed material vary depending on the type of mineral deposit (Table 1).¹⁸ Once the seabed material is extracted, it would be transported to land for mineral processing.

Regulations for Deep-Seabed Mining in Areas Beyond National Jurisdiction

Several international bodies and agreements address deep-seabed mining activities that could occur in ABNJ. Some of these regulate international exploration and exploitation of seabed minerals or provide guidance to prevent harm to the marine environment. The following sections describe the international bodies and agreements that regulate deep-seabed mining in ABNJ, as well as relevant U.S. domestic laws.

United Nations Convention on the Law of the Sea and the 1994 Agreement

In 1982, the UN Convention on the Law of the Sea (UNCLOS) established a framework governing activities on, over, and under the world's ocean. A recurring theme throughout UNCLOS is the "protection and preservation of the marine environment."¹⁹ UNCLOS specifies that necessary measures be taken to protect the marine environment with respect to certain activities. For example, Article 145 states

Necessary measures shall be taken in accordance with this Convention with respect to activities in the Area to ensure effective protection for the marine environment from harmful effects which may arise from such activities. To this end the Authority shall adopt appropriate rules, regulations and procedures for inter alia:

(a) the prevention, reduction and control of pollution and other hazards to the marine environment, including the coastline, and of interference with the ecological balance of the marine environment, particular attention being paid to the need for protection from harmful effects of such activities as drilling, dredging, excavation, disposal of waste, construction and operation or maintenance of installations, pipelines and other devices related to such activities;

(b) the protection and conservation of the natural resources of the Area and the prevention of damage to the flora and fauna of the marine environment.

In 1982, the United States and some other industrialized countries did not sign the convention or announced they could not ratify it without important changes to Part XI of UNCLOS, which deals with deep-seabed resources in ABNJ.²⁰ UNCLOS refers to resources recovered from ABNJ as minerals, which includes all solid, liquid, or gaseous mineral resources as well as polymetallic nodules at or beneath the seabed.²¹ UNCLOS also considers minerals collected from ABNJ as common heritage of mankind, meaning seabed resources are available for everyone's use and benefit, including Small Island Developing States, Landlocked Developing Countries, and Least Developed Countries.²² The Reagan Administration was not comfortable with some of these seabed mining provisions.²³

In 1994, the UN General Assembly adopted a resolution opening the Agreement Relating to the Implementation of Part XI of the United Nations Convention on the Law of the Sea (the 1994 Agreement), which amended UNCLOS Part XI by removing many of the provisions objectionable to industrialized nations.²⁴ Following the adoption of the 1994 Agreement, UNCLOS entered into force. In October 1994, President Clinton submitted UNCLOS and the 1994 Agreement as a package to the Senate for advice and consent to ratification. To date, the Senate has not ratified UNCLOS or the 1994 Agreement, but members of the executive branch have stated that some (but not all) portions of UNCLOS reflect customary international law.²⁵ For example, Presidential Proclamation 5030 established the EEZ of the United States in accordance with UNCLOS and "assert[ed] the sovereign rights and jurisdiction of the United States in its EEZ and confirm[ed] the rights and freedoms of all states, as provided under international law."²⁶

International Seabed Authority

UNCLOS established the ISA, an autonomous organization that regulates and controls mineral-related activities in ABNJ for parties to UNCLOS.²⁷ According to the ISA, it has a "mandate to ensure the effective protection of the marine environment from harmful effects that may arise from deep-seabed-related activities."²⁸ Deep-seabed activities include exploration of the seabed and exploitation of seabed mineral resources. Parties to UNCLOS are ipso facto members of the ISA.²⁹ As a UN member nation, the United States has an observer delegate status at the ISA.³⁰

As of April 25, 2025, the ISA had issued 31 exploration contracts to public and private mining enterprises for seabed mineral resources.³¹ The ISA has never rejected an application for an exploration contract.³² The ISA has issued 17 exploration contracts for polymetallic nodules in the Clarion-Clipperton Zone (CCZ; Figure 2).³³ The CCZ is estimated to contain more copper, cobalt, nickel, and manganese than all known land deposits combined.³⁴ Because the United States is not a party to UNCLOS, the United States cannot sponsor companies interested in seeking ISA contracts for exploration or exploitation of seabed mineral resources through the ISA framework. Under domestic law, the United States has authorized exploration licenses to U.S.-based companies in the CCZ (see "Deep Seabed Hard Mineral Resources Act and Other Applicable U.S. Laws," below).³⁵

Figure 2. Clarion-Clipperton Fracture Zone (CCZ)

Source: Map created by CRS using International Seabed Authority (ISA), "Maps," https://www.isa.org.jm/exploration-contracts/maps/; and National Oceanic and Atmospheric Administration (NOAA), Deep Sea Mining: A Report to Congress, 1995, p. 6; and ESRI. Notes: APEI = Areas of Particular Environmental Interest, which refers to no-mining zones as designated by the ISA to protect the full range of biodiversity and habitats; DSHMRA = Deep Seabed Hard Mineral Resources Act (30 U.S.C. §§1441 et seq.); and UK = United Kingdom. Most commercial interest in deep-seabed mining focuses on the CCZ. The CCZ is approximately 1.7 million square miles (up to 3.4 miles beneath the ocean's surface), spanning an area as wide as the continental United States on the Pacific seafloor. Since 2001, ISA has awarded 17 exploration contracts for polymetallic nodules in the CCZ. In addition to APEIs, the ISA also designates reserved areas to ensure developing countries have access to mineral resources in areas beyond national jurisdiction. NOAA issued two exploration licenses in the CCZ in 1984 that have been extended through June 2027 pursuant to DSHMRA. For more information about ISA exploration contracts and U.S. exploration licenses issued by the NOAA pursuant to DSHMRA in the CCZ and the duration of these contracts and U.S. licenses, see CRS Infographic IG10053, Seabed Mining in the Clarion-Clipperton Zone, by Caitlin Keating-Bitonti, Corrie E. Clark, and Emma Kaboli.

The ISA has yet to develop a regulatory regime for extraction of seabed minerals and therefore has not issued exploitation contracts. The issuance of exploitation contracts would include information about mining operations and actions to minimize harm to marine habitats and species at the proposed site.³⁶ In 2014, the ISA began to draft standards and guidelines for exploitation of seabed minerals in ABNJ and initially set a self-imposed deadline of 2020 for the release of its "Mining Code," which was delayed due to the Coronavirus Disease 2019 pandemic.³⁷

In 2021, the Republic of Nauru, a small island country located northeast of Australia in the Pacific Ocean, notified the ISA of its sponsorship of Nauru Ocean Resources Inc. (NORI; a subsidiary of The Metals Company [TMC], a Canadian firm) and its intention to mine the CCZ by early 2026.³⁸ The Republic of Nauru claimed its efforts to mine the seabed would support the global transition to clean energy technologies and would help reduce carbon emissions.³⁹

The Republic of Nauru's application triggered a legal provision within UNCLOS that compels the ISA to establish standards and guidelines for mining deep-sea resources while minimizing environmental risks.⁴⁰ According to the provision, commonly referred to as the two-year rule, the ISA must finalize its deep-seabed mining regulations within two years (i.e., by summer 2023).⁴¹ The ISA did not meet this two-year deadline and pushed the deadline to 2025.⁴² Outstanding matters to be considered within the ISA's regulations for exploitation of seabed minerals could include the following, for example:

• Threshold of environmental harm to apply when assessing applications, including knowledge of environmental baseline data
• Processes relating to the preparation and evaluation of environmental plans
• Monitoring programs
• Environmental performance guarantees
• Environmental compensation fund
• Adjacent coastal states and transboundary harm⁴³

On January 1, 2025, Leticia Carvalho began her four-year term as Secretary-General of the ISA, replacing Michael Lodge, who had held the position since 2017.⁴⁴ Carvalho has been reported as saying commercial-scale deep-seabed mining should not start until environmental regulations are finalized.⁴⁵ However, ISA Council decisions provide that if an ISA exploitation application is submitted before the exploitation regulations have been adopted, the council will consider the process for reaching a decision on such an application at its next meeting.⁴⁶ TMC announced that NORI and the Republic of Nauru intend to submit their ISA exploitation application on June 27, 2025.⁴⁷

The London Convention

The principal international agreements that address marine pollution are the 1972 Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, known as the London Convention,⁴⁸ and the 1996 Protocol to the London Convention, known as the London Protocol.⁴⁹ The United States is a party to the London Convention and is not a party to the London Protocol. Under Article XII of the London Convention, parties pledge to take measures to protect the marine environment against pollution. Included among the list of pollution sources are "wastes or other matter directly arising from, or related to the exploration, exploitation and associated off-shore processing of sea-bed mineral resources."

Deep Seabed Hard Mineral Resources Act and Other Applicable U.S. Laws

In 1980, Congress passed the Deep Seabed Hard Mineral Resources Act (DSHMRA; P.L. 96-283) as an interim measure to allow U.S. citizens to proceed with seabed mineral exploration and recovery until an international regime was in place (i.e., UNCLOS).⁵⁰ The 96^th Congress stated among the findings of DSHMRA that "the nations of the world, including the United States, will benefit if the hard mineral resources [, including nickel, copper, cobalt, and manganese,] of the deep seabed beyond limits of national jurisdiction can be developed and made available for their use."⁵¹ Further, the 96^th Congress stated the purposes of DSHMRA are to "encourage the successful conclusion of a comprehensive [UNCLOS],"⁵² and to "assure that such exploration and recovery activities are conducted in a manner which will encourage the conservation of such resources, protect the quality of the environment, and promote the safety of life and property at sea,"⁵³ among others. For example, the act directed the National Oceanic and Atmospheric Administration (NOAA) to "expand and accelerate a program assessing the effect on the environment from exploration and commercial recovery activities," including the long- and short-term effects on deep-seabed species in ocean areas where deep-seabed mining activities likely would occur.⁵⁴

DSHMRA establishes a framework for authorizing U.S. citizens to explore for and recover minerals from the seabed in ABNJ. Congress authorized NOAA to issue exploration licenses and commercial recovery permits to U.S. citizens for deep-seabed mining activities.⁵⁵ After NOAA receives an application by an entity seeking an exploration license or commercial recovery permit and before it issues the license or permit, NOAA is required to prepare and publish an environmental impact statement for its issuance of the license or permit.⁵⁶ The National Environmental Policy Act (42 U.S.C. §§4321-4347) is the source of the substantive requirements for preparing an environmental impact statement.

The lack of accession by the United States to UNCLOS does not preclude NOAA from issuing exploration licenses or commercial recovery permits pursuant to DSHMRA.⁵⁷ In 1984, NOAA issued exploration licenses for four sites located in the CCZ, predating the establishment of the ISA in 1994.⁵⁸ NOAA has not issued any exploration licenses since 1984, although the agency has approved extension requests. To date, two exploration licenses (USA-1 and USA-4), both held by Lockheed Martin, remain active pursuant to DSHMRA and in effect through June 2, 2027 (Figure 2).⁵⁹ As of April 25, 2025, NOAA has not issued commercial recovery permits under DSHMRA. Commercial recovery permits issued by NOAA may not be recognized by parties to UNCLOS, and it is possible the ISA could issue exploitation contracts to a company sponsored by a nation party to UNCLOS in the same area.⁶⁰ Without the United States being a party to UNCLOS, U.S. citizens issued licenses or permits by NOAA would have no legal recourse under UNCLOS mechanisms to protect their claim to explore and/or recover seabed minerals in ANBJ.

U.S. companies pursuing deep-seabed mining activities in ABNJ may be subjected to other U.S. federal laws, including the Marine Mammal Protection Act (16 U.S.C. §§1361-1423h). In addition, Section 109(e) of DSHMRA provides that any discharge of a pollutant from a vessel or other floating craft associated with deep-seabed mining activities is subject to the provisions of the Clean Water Act (33 U.S.C. §§1251-1387).⁶¹

Potential Marine Environmental Impacts of Seabed Mining

The potential effects of seabed mining on the marine environment remain incompletely understood. This is in part because commercial-scale deep-seabed mining in ABNJ has yet to occur.

Seabed mining companies have worked with scientists to collect environmental and biological data in deep-sea areas with potential for mineral deposits.⁶² These companies are collecting and sharing these data with the ISA—a requirement of ISA exploration contracts—in part to understand the potential impacts of seabed mining activities.⁶³ Although scientists have worked with seabed mining companies to establish environmental baselines, some stakeholders may perceive their scientific research as a potential conflict of interest.⁶⁴ While some may call for a third party or independent scientific institution to collect deep-sea data, this type of research may be cost prohibitive for such researchers.⁶⁵

Mineral deposits occur across different ocean environments and would require different machinery and technology to collect seabed material (see Figure 3 in the text box, below), which means it may be challenging to extrapolate understanding of marine environmental impacts from one area of the ocean to another. Some potential seabed mining impacts to the marine environment are described below.

Some species inhabiting the deep sea live under cold conditions without sunlight and survive on little food.⁶⁶ To be successful under such conditions, deep-sea species have low metabolic rates—they move slowly, live for a long time, and take many years to reproduce.⁶⁷ In general, these traits mean species may be slow to recover from disturbances, making them potentially vulnerable to deep-sea exploitation activities, such as seabed mining, and making the deep-sea environment potentially susceptible to biodiversity loss.⁶⁸

Sediment dispersal by seabed mining machinery disturbing seafloor deposits has the potential to impact environments immediate and adjacent to the mined area (see Figure 3 in the text box, below).⁶⁹ The distance to which sediment disperses through the water column primarily depends on the presence of ocean currents and, if near the surface of the ocean, wave energy. Suspended sediment in the water column could reduce water quality and clarity. The dispersion of seafloor sediment may threaten certain groups of benthic (i.e., living on or within the seafloor) invertebrate organisms in specific ways:

• Deposit feeders, organisms that feed on organic matter that settled onto the seafloor, may be impacted by sediment diluting or burying their food resources.⁷⁰
• Suspension feeders (also known as filter feeders), organisms that filter small food particles directly from the water, may be affected by suspended sediment clogging the water column.⁷¹

An additional concern for benthic organisms is that seabed mining machinery could crush, smother, or disperse them while disturbing their habitats.⁷²

The removal of nodules and other hard mineral resources from the seabed also may impact species living or depending on these resources.⁷³ For example, some organisms require a hard surface, such as a mineral nodule, to attach their bodies to in order to live and grow. Some species of sponges and some microbes live on seabed nodules,⁷⁴ and a species of deep-sea octopus lays its eggs on sponges attached to seabed nodules.⁷⁵ Because deep-sea nodules form over millions of years,⁷⁶ their removal in an area of the seafloor could equate to the permanent loss of a part of the marine habitat that some deep-sea species depend on for their survival.⁷⁷

Noise and vibration associated with seabed mining operations may affect the behaviors of marine mammals and other animals living near the ocean's surface.⁷⁸ Sound waves travel through the ocean approximately four times faster than they can travel through air and could increase the ambient background noise level in areas up to 500 kilometers away from the mining site, potentially impacting animals in that radius.⁷⁹ Noise pollution from mining operations may mask communication and echolocation sounds of cetaceans (whales, porpoises, and dolphins), affecting their abilities to detect and avoid predators and to find food and mates.⁸⁰ It also may cause temporary or permanent hearing loss in some marine mammals and may increase their stress levels.⁸¹

The processing of recovered seabed material at the ocean surface and its transport to land may have impacts near or at the ocean surface. For example, seabed material may be processed on a production support vessel (PSV) or surface-based mining platform and seafloor sediment discarded back into the ocean may cloud the near surface water column (see Figure 3 in the text box, below), potentially inhibiting photosynthesis in some plankton.⁸² Collected seabed material and water also may potentially overflow off the PSV or mining platform.⁸³ In addition, ship traffic associated with seabed mining operations may pose a threat to animals living near the ocean's surface. The increased potential for a vessel strike is one concern.⁸⁴ Another concern would be the discharge of ballast water and other wastes, including marine debris, from mining vessels.⁸⁵

Some extractive activities, including seabed mining, could disturb the natural processes (i.e., microbes) that regulate carbon in the deep sea in addition to existing carbon buried in deep-sea sediments.⁸⁶ Some scientists speculate that activities that affect carbon burial in sediments could have "far-reaching effects on carbon sequestration that in turn is connected to climate regulation,"⁸⁷ and others have stated that "deep seabed mining may be directly at odds with current climate goals if such regulatory services [provided by microbial communities] are degraded."⁸⁸ Other stakeholders state that the scale at which seabed mining would take place would have minimum impact on net deep-sea carbon storage.⁸⁹

Proponents of seabed mining that is "properly managed with appropriate governance safeguards" argue that sourcing minerals from the deep sea has the potential to have less pollution (e.g., tailings, waste), impacts on freshwater sources, and social impacts (e.g., human fatalities, injuries, health effects) compared with traditional land-based open-pit and underground mining.⁹⁰ Instances of terrestrial mining have been associated with drinking water contamination, air pollution, and alteration of landscapes, among other impacts.⁹¹ The potential primary impacts of seabed mining would be on the marine organisms and ocean carbon storage, which could have secondary effects on humans.

Proposed Seabed Mining Operations While no commercial-scale seabed operations currently take place in areas beyond national jurisdiction, the figure below illustrates some of the machinery proposed to mine polymetallic sulfides deposits at hydrothermal vents, ferromanganese crusts at seamounts, as well as machinery and technologies proposed to collect polymetallic nodules from the deep-sea abyssal plain. Figure 3. Proposed Machinery and Technology for Collecting Seabed Minerals Source: Illustration created by CRS, modifying figure 4 in Kathryn Miller et al., "An Overview of Seabed Mining Including the Current State of Development, Environmental Impacts, and Knowledge Gaps," Frontiers in Marine Science, vol. 4 (2018) and using Allseas, "Hidden Gem," https://allseas.com/equipment/hidden-gem/; International Seabed Authority, CARMUS Inspection Report 01/2023, February 21, 2023, pp. 1-38, https://www.isa.org.jm/wp-content/uploads/2023/02/ISA_inspection_report_NORI_mining_collector_system_test.pdf; Impossible Metals, Inc., "Robotic Collection System," https://impossiblemetals.com/technology/robotic-collection-system/; and Wendy Laursen, "The Nodule Collectors Are Lining Up, Ready to Go," Maritime Magazine, March 2024, https://www.maritimemagazines.com/offshore-engineer/202403/the-nodule-collectors-are-lining-up-ready-to-go/. Notes: Proposed mining machinery, collection vessels, and autonomous underwater vehicles for seabed mining operations at hydrothermal vents, on the deep-sea abyssal plain, and at seamounts. Depths depicted in meters refers to the typical depth at which these seafloor features (and potential mineral deposits) are located below the surface of the ocean. Some seabed mining approaches require a production support vessel (PSV) and a transport vessel. A PSV launches the mining machinery or collector vehicle and provides power to it while operating on the seafloor. Collected seabed material is lifted via a riser pump to the PSV, where the desired seabed material would be separated from water and sediment. The water and sediment is returned to the ocean via a return pipe. A transportation vessel would ship the seabed material to land where it would be processed and refined into useable metals. For polymetallic sulfides (or seafloor massive sulfide) deposits at hydrothermal vents, remotely operated mining machines have been proposed to cut and drill into the hydrothermal vent chimney to crush and extract internal minerals. The resulting slurry (i.e., mix of water and crushed material) would be transported via a riser pump to a production support vessel (PSV). At the ocean surface, the fine crushed material would be separated from the water. The water and discarded material would be returned to the ocean at an unspecified water depth via a return pipe, creating a sediment plume at the discharged depth. For ferromanganese crusts (or cobalt-rich crusts) at seamounts, remotely operated mining machines have been proposed to scrape across the surfaces of the seamount (or other geologic features) to remove surficial mineral crusts. The resulting slurry would be transported via a riser pump to a PSV. At the ocean surface, the fine crushed material would be separated from the water. The water and discarded material would be would be returned to the ocean at an unspecified water depth via a return pipe, creating a sediment plume at the discharged depth. In addition, large whole rock material has been proposed be lifted in buckets to a PSV. For polymetallic nodules, remotely operated collector vehicles fitted with caterpillar-like tracks use a water stream aimed at nodules laying on the seafloor to create a pressure drop and suction effect to lift sediment with nodules into a collector system. Some companies have proposed using sonar technology on the collector vehicles to identify the location of nodules. As a vehicle moves across the seafloor, a diffusor at the rear of the vehicle would emit seafloor sediment back into the environment, forming a sediment plume. The slurry (i.e., mix of water, sediment, and nodules) would be transported via a riser pump to a PSV. At the ocean surface, nodules would be separated and the sediment and water mix would be returned to the ocean at an unspecified water depth via a return pipe, creating a sediment plume at the discharged depth. One company has proposed an autonomous underwater vehicle (AUV) that hovers over the seafloor and uses robotic arms with a vision system to pick individual nodules from the seafloor. Once the AUV is full, it would return to the support vessel to offload nodules and have its battery recharged. For each of these three seabed mineral deposits, the desired material would be transported to a processing and refining facility on land. Sources: Allseas, "Hidden Gem," https://allseas.com/equipment/hidden-gem/; Deep Sea Mining, "Mining Subsea Minerals – How It Works," https://deepseamining.ac/how_it_works; International Seabed Authority, CARMUS Inspection Report 01/2023, February 21, 2023, pp. 1-38, https://www.isa.org.jm/wp-content/uploads/2023/02/ISA_inspection_report_NORI_mining_collector_system_test.pdf; Impossible Metals, Inc., "Robotic Collection System," https://impossiblemetals.com/technology/robotic-collection-system/; Wendy Laursen, "The Nodule Collectors Are Lining Up, Ready to Go," Maritime Magazine, March 2024, https://www.maritimemagazines.com/offshore-engineer/202403/the-nodule-collectors-are-lining-up-ready-to-go/; and The Metals Company, "Nodules," https://metals.co/nodules/.

Issues for Congress

Congress may be interested in how potential deep-seabed mining in ABNJ may impact deep-sea habitats and their species as well as demand for and U.S. importation of land-based minerals, including critical minerals.⁹² With respect to access to seabed minerals in ABNJ, Congress may consider the potential implications of the United States not being a party to UNCLOS or the potential benefits, or consequences, of the U.S. ratification of UNCLOS.

On April 24, 2025, President Trump issued an executive order titled "Unleashing America's Offshore Critical Minerals and Resources," which, among other things, directs the Administrator of NOAA, in consultation with the Secretary of State and the Secretary of the Interior, acting through the Director of the Bureau of Ocean Energy Management (BOEM), to "expedite the process for reviewing and issuing seabed mineral exploration licenses and commercial recovery permits" in ABNJ under DSHMRA.⁹³ Executive branch activities may affect issues of congressional interest related to seabed mining, such as potentially diversifying critical mineral supply chains and developing capabilities for processing seabed minerals in the United States. Congress may consider the benefits of U.S. companies pursing seabed mining activities under NOAA authorities and regulations and concerns about the environmental and geostrategic impacts of such activities. The United States is not a party to UNCLOS, so whether and how U.S. policies, as expressed in the new executive order, may conflict with the ISA framework for seabed mining or the policies of UNCLOS signatories is not clear.⁹⁴

U.S. Importation of Land-Based Minerals and Seabed Mining Exploration Efforts by Selected Foreign Governments

Because critical minerals, including rare earth elements (REEs), can be found in land and ocean deposits, Congress could consider weighing the potential marine environmental impacts of seabed mining alongside the environmental impacts associated with terrestrial mining. Some may argue seabed mining could reduce U.S. dependency on importing certain land-based minerals, such as cobalt.⁹⁵ For example, a 2024 study by the U.S. Geological Survey (USGS) identified that China had a monopoly over cobalt battery materials.⁹⁶ China owns or finances mines in the Democratic Republic of the Congo, some of which have been associated with unsafe working conditions and forced labor.⁹⁷ Dependence on foreign sources of minerals may lead to U.S. uncertainties in supply ranging from cost instability to supply disruptions. For example, China has restricted or prohibited the export of certain critical minerals to the United States. Some of these export-controlled critical minerals (e.g., gallium, scandium, yttrium) by China occur in seabed deposits (Table 1).⁹⁸ Some stakeholders also may look to seabed mining to reduce dependence on sources with weak protective labor and environmental standards and practices.⁹⁹ In addition to seabed minerals as potential alternative sources for critical minerals, the Biden Administration identified recycling and recapture of minerals from waste or mine tailings as other options.¹⁰⁰

Deep-sea resources may contribute to meeting the changing global demand for some critical minerals, such as cobalt. The ISA has issued 31 exploration contracts to public and private mining enterprises for seabed mineral resources.¹⁰¹ Of these ISA exploration contracts, China currently holds five exploration contracts: three contracts for polymetallic nodules (two of these three are for the CCZ [Figure 2]); one contract for polymetallic sulfides; and one contract for cobalt-rich ferromanganese crusts. The Russian Federation currently holds four ISA exploration contracts: two contracts for polymetallic nodules located in the CCZ, one of which is a joint contract between six member nations of the ISA (Figure 2); one ISA exploration contract for polymetallic sulfides; and one ISA exploration contract for cobalt-rich ferromanganese crusts. Some Members of Congress have expressed concern about China's dominance of the global critical mineral market place, pointing to China's five ISA exploration contracts (the most of any country) and China's control over a large portion of terrestrial mines (located in China or Chinese-owned in other countries).¹⁰² In addition to mining critical minerals, in 2022 China processed approximately 31% of the nickel, 74% of the cobalt, and 90% of REEs extracted globally.¹⁰³

According to the Department of Commerce, the United States currently "lacks domestic processing and manufacturing capabilities for some critical minerals,"¹⁰⁴ including those derived from seabed deposits. In the 118^th Congress, some Members proposed that domestic processing of seabed minerals could reduce U.S. dependence on critical minerals supplied by non-allied countries. For example, H.Rept. 118-125, the House Armed Services Committee (HASC) report, which accompanied its reported version of the National Defense Authorization Act for Fiscal Year 2024 (H.R. 2670), directed the Department of Defense (DOD) to submit a report to the committee assessing the processing of polymetallic nodules domestically.¹⁰⁵ The committee report notes that while the United States holds no ISA contracts, "there remains opportunity to evaluate domestic processing and refining of seafloor resources from the contracts held by allied [UNCLOS] parties and domestic partners in international waters." Similarly, H.Rept. 118-529, the HASC report accompanying its reported version of the Servicemember Quality of Life Improvement and National Defense Authorization Act for Fiscal Year 2025 (H.R. 8070), authorized a DOD study to assess the feasibility of improving U.S. capabilities for refining polymetallic nodules for defense purposes.¹⁰⁶ Some stakeholders have proposed Texas as a potential site for a smelting or refining facility for producing critical minerals from polymetallic nodules.¹⁰⁷ In 2023, some Members of Congress had supported a potential seabed mineral processing facility in Texas and asked DOD to support TMC's application for funding to develop a Texas processing facility.¹⁰⁸ For the United States to domestically process polymetallic nodules derived from ABNJ, the ISA would need to issue exploitation contracts. Some Members in the 118^th Congress called on the ISA to adopt exploitation regulations because the domestic processing and refining of critical minerals, including polymetallic nodules from the CCZ, is in the national interest of the United States.¹⁰⁹

Some Members of Congress have proposed securing a reliable supply of critical minerals and REEs through strategic partnerships. For example, S. 429 in the 119^th Congress would authorize the President, through the U.S. Trade Representative, to negotiate and enter into trade agreements related to critical minerals with allied countries. The bill also would amend the Defense Production Act of 1950 to include such countries in the definition of a domestic source, potentially making related enterprises eligible for U.S. financial incentives.¹¹⁰ In addition, some countries with operating critical mineral processing facilities also have comprehensive free-trade agreements with the United States; these countries may provide opportunities for collaboration enabling the United States to bolster U.S. critical minerals supply chains, including those potentially derived from seabed mining. For example, Colombia, the Dominican Republic, and South Korea have free-trade agreements with the United States,¹¹¹ and each has an operating smelting facility.¹¹² Japan and the United States have concluded several limited trade deals, including a critical minerals agreement.¹¹³ Japan has three operating smelting facilities.¹¹⁴ The U.S. Department of the Treasury has designated Colombia, the Dominican Republic, Japan, and South Korea, among other countries,¹¹⁵ as U.S. free-trade agreement partners for the purposes of meeting critical minerals sourcing requirements in the clean vehicle tax credit under the Inflation Reduction Act of 2022 (IRA; P.L. 117-169).¹¹⁶ Some companies may be interested in sourcing certain minerals derived from seabed mining in order to receive a clean vehicle tax credit under the IRA.¹¹⁷ Congress also may consider how U.S. tariffs could impact U.S. trade relations with countries pursuing critical minerals and its effect on seabed mining activities.¹¹⁸

U.S. Ratification of United Nations Convention on the Law of the Sea

The U.S. Senate might consider the ratification of UNCLOS.¹¹⁹ For consecutive Congresses between the 115^th and 118^th Congress, some Members have introduced resolutions calling on the U.S. Senate to give its advice and consent to the ratification of UNCLOS.¹²⁰ Members of Congress and other stakeholders may call for the United States to join UNCLOS for several reasons related to deep-seabed mining issues. Some stakeholder proposed reasons for the United States to join or not join UNCLOS are discussed below.

Deep-Seabed Mining Activities in Areas Beyond National Jurisdiction

By ratifying UNCLOS, the United States would become a member of the ISA. As a member of the ISA, the United States could sponsor U.S. companies seeking ISA contracts. Currently, U.S. companies would have to establish a subsidiary in a nation party to UNCLOS to seek ISA contracts. For example, the United Kingdom (UK) arm of Lockheed Martin established UK Seabed Resources.¹²¹ Through sponsorship of the UK of Great Britain and Northern Ireland, UK Seabed Resources held two ISA exploration contracts for polymetallic nodules in the CCZ.¹²² On March 16, 2023, Loke Marine Minerals, a Norwegian company, acquired 100% of UK Seabed Resources.¹²³ This acquisition also included the transfer of UK Seabed Resources' two ISA-issued exploration contracts to Loke Marine Minerals (Figure 2).¹²⁴ However, Loke Marine Minerals filed for bankruptcy in April 2025, claiming "it was difficult to raise capital" due to uncertainty over the ability of the ISA to adopt exploitation regulations in the near future.¹²⁵

Some stakeholders who oppose U.S. ratification of UNCLOS contend that the United States already has the authority to explore and recover seabed minerals in ABNJ.¹²⁶ However, some U.S.-based companies may find it too risky to pursue NOAA exploration licenses for seabed mining in the absence of U.S. ratification of UNCLOS. Lack of accession by the United States to UNCLOS has not precluded NOAA from extending two DSHMRA exploration licenses to Lockheed Martin through 2027.¹²⁷ However, in December 2021, the ISA established an Area of Particular Environmental Interest—a no-mining zone that seeks to protect the full range of biodiversity and habitats—that partially overlaps with one of the Lockheed Martin's DSHMRA exploration licenses (refer to USA-1 in Figure 2).¹²⁸ Conflicting claims between DSHMRA exploration licenses and ISA contracts could potentially deter financiers from backing U.S.-authorized deep-seabed mining projects.¹²⁹

On March 27, 2025, TMC announced that its U.S. subsidiary, The Metals Company USA LLC (TMC USA), had formally initiated a process with NOAA to apply for exploration licenses and commercial recovery permits under DSHMRA.¹³⁰ As discussed above, on April 24, 2025, President Trump directed NOAA to "expedite the process for reviewing and issuing seabed mineral exploration licenses and commercial recovery permits" in ABNJ under DSHMRA.¹³¹ Congress may consider the potential geopolitical consequences of U.S. companies pursing seabed mining licenses and permits under DSHMRA. Because TMC holds two ISA exploration contracts for polymetallic nodules in the CCZ, through sponsorships with Republic of Nauru and the Kingdom of Tonga,¹³² some stakeholders speculate that TMC USA's actions may be part of "a tactic to put pressure on the ISA" to adopt its exploitation regulations.¹³³ The adoption of the ISA's exploitation regulations would allow seabed mining companies to apply for exploitation contracts and potentially proceed with commercial-scale mining through the ISA framework.

International Seabed Authority Decisionmaking

During the negotiation of the 1994 Agreement, one permanent seat on the 36-member ISA Council was created for the country "having the largest economy in terms of gross domestic product" on the date UNCLOS entered into force.¹³⁴ When UNCLOS entered into force on November 16, 1994, the United States had the largest economy. If the United States ratified UNCLOS, the United States would occupy the only permanent seat on the ISA Council.¹³⁵ The Council establishes ISA policies, proposes rules of procedure, enters into agreements with the United Nations or other international organizations, exercises control over activities occurring on or within the seabed in ABNJ (for parties to UNCLOS), and disapproves areas for exploitation, among other powers.¹³⁶ In general, the Council makes decisions by consensus for administrative, budgetary, and financial matters, including distribution fees.¹³⁷

The United States could formally participate in negotiations on ISA matters if it was a member of the ISA. For example, negotiations are ongoing for ISA regulations for the exploitation of mineral resources in ABNJ.¹³⁸ Some stakeholders contend that the United States should ratify UNCLOS to formally participate in the development of these regulations.¹³⁹ According to the U.S. Department of State, as an observer delegate to the ISA, United States' input has been generally respected and accepted in the drafting of the ISA's exploitation regulations.¹⁴⁰ Other matters, such as a mechanism for the equitable sharing of financial and other economic benefits derived from deep-seabed mining activities, have yet to be developed and adopted by the ISA.¹⁴¹

U.S. Federal Research to Study Seabed Mining Impacts and Associated Mining Technologies

Exploration of deep-sea habitats can provide baselines for understanding whether—and to what degree—these habitats and their species are vulnerable or resilient to disturbance or change. Under the Biden Administration, the United States had taken the position that "a robust understanding of the marine environment and the potential impacts of seabed mining activities on the ocean, impacted species and ecological communities, and the climate" is needed to inform the ISA's exploitation regulations.¹⁴² NOAA's 1975-1980 Deep Ocean Mining Environmental Studies Project and subsequent projects through the 1990s as directed by Congress under DSHMRA were limited to the biological effects of increased sedimentation on the seafloor.¹⁴³ In more recent years, NOAA has collaborated with the BOEM and USGS to study a 1970s test site for seabed mining equipment on the Blake Plateau, offshore the Georgia coast, "to quantify the extent of the impacts, search for visual signs of ecosystem recovery, plan for additional research, and, ultimately, inform reviews, future decisions, and mitigation measures related to deep-sea mining in other areas."¹⁴⁴ Congress may consider directing and/or appropriating more funding to NOAA, BOEM, USGS, and other relevant agencies, to conduct additional exploration campaigns or research studies designed to establish environmental baseline data to inform seabed mining activities.¹⁴⁵

Some stakeholders have called for the implementation of environmental safeguards before ISA permits deep-sea exploitation activities.¹⁴⁶ Other stakeholders point to the lack of environmental baseline data for deep-sea habitats as one reason to delay or ban deep-seabed mining in ABNJ.¹⁴⁷ Several technology companies (e.g., Apple, Google, and Samsung) and automakers (e.g., BMW, Volkswagen, Volvo) have announced support for a moratorium on seabed minerals being used in electric vehicle batteries and other technologies until seabed mining activities can be performed in a way that protects the marine environment.¹⁴⁸ More than 30 foreign governments also have called for a moratorium on deep-seabed mining. Although France holds an ISA exploration license in the CCZ (Figure 2), France is among the governments calling for a moratorium. France's State Secretary for the Sea has said that France will continue to hold its ISA contract and use it for "more research, more science, more data" to better understand the deep sea.¹⁴⁹ Some Members of Congress signed a letter urging President Biden to "support a precautionary pause or moratorium on deep-seabed mining until and unless there is sufficient scientific information and knowledge of the deep sea."¹⁵⁰ In the 119^th Congress, some Members of Congress introduced H.R. 663 instructing the President to direct U.S. representatives to international organizations (e.g., the ISA) to call for a moratorium on deep-seabed mining.

Some Members of Congress proposed legislation in the 119^th Congress that could improve understanding of seabed mining impacts. For example, H.R. 664 would authorize NOAA to enter into an agreement with the National Academies of Sciences, Engineering, and Medicine to "conduct a comprehensive study of the environmental impacts of mining activities on the deep seabed and the Outer Continental Shelf." With an improved understanding of these marine environmental impacts, Congress might consider how amending DSHMRA or other laws could ameliorate some of the potential negative effects on the ocean of U.S. licensed or permitted seabed mining activities.

Congress might consider how mining technologies for the recovery of seabed minerals has evolved since DSHMRA was enacted and amend relevant aspects of the law to better reflect the potential impacts these technologies could have on deep-sea habitats and deep-sea organisms.¹⁵¹ For example, Impossible Metals, Inc., a U.S. seabed mining company, is developing an autonomous underwater vehicle (AUV) fixed with robotic arms and computer vision system that would hover over the seafloor to pick up individual polymetallic nodules.¹⁵² Impossible Metals posits their AUV would have minimum sediment disturbance compared to other collection approaches and its computer vision could help avoid nodules with attached marine life.¹⁵³

Congress may consider the level of funding to certain federal agencies that support the research and development of seabed mining technologies. Congress could determine if agencies should receive increased levels of funding to meet certain seabed mining objectives or if current funding levels are sufficient. For example, the Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E), authorized by P.L. 110-69 (commonly known as the America COMPETES Act), supports transformational energy technology research projects. ARPA-E has funded several projects related to seabed mining, including the design and development of technologies for seabed mineral collection and monitoring systems to assess sediment disturbance associated with seabed mining.¹⁵⁴

Footnotes