Excavating minerals from the deep sea can expose humans to hazardous chemicals

Disturbing sea beds can have negative effects on human health. A temporary ban is needed until we know the risks.

By Kimberly Yang

In the pitch black of the deep ocean floor, treasure awaits: precious rocks rich in cobalt, nickel, lithium and other critical minerals. Batteries, electronics, and the shift to green energy rely on resources like these, making the untapped reservoir of deep sea mining tantalizing. But retrieving this hidden swatch of treasure risks exposing human health to dangers that so far have not been sufficiently understood.

To date, the International Seabed Authority (ISA) has not set a code of regulations governing deep sea mining in international waters, nor has it imposed a moratorium, otherwise known as a temporary ban. In April, the Trump administration issued an executive order expediting deep sea mining licenses in international waters for U.S.-based companies, essentially circumventing the ISA. The next day, The Metals Company, a deep sea mining exploration company, applied to the National Oceanic and Atmospheric Administration (NOAA) for the first deep sea mining permits in the Clarion-Clipperton Zone in the Pacific Ocean, a region in international waters and not under U.S. jurisdiction.

This executive order pushes to accelerate US participation in seabed mining, ignoring the warnings from scientists and human rights advocates about the profoundly harmful consequences for marine ecosystems and coastal human communities. Turning a blind eye to these cautions signals that the impact on human health—reinforced inequities, pollutant-induced diseases, and more—is being overshadowed by geopolitics and the rush to obtain minerals.

To proceed with deep sea mining would be to rush into exploitation of and profit from the ocean’s unexplored and mysterious depths. Before we fully understand the consequences of deep sea mining, the only ethical and responsible choice is a global moratorium on deep sea mining. There should be no deep sea mining permits issued until rigorous and comprehensive research has been conducted, meaningful regulation has been passed, and equitable protections are in place to protect ecosystems and human health against the ripple effects of mining the deep sea.

Mining the deep sea gambles with both the environment and human health, with the winnings unequally distributed. Any payoff only benefits the handful of early investors and CEO’s in deep sea mining companies. The losers lose big—massive debt, environmental damage, and exploitation. Papua New Guinea is a prime example. Nautilus Minerals, a Canada-based deep sea mining company, partnered with Papua New Guinea for seabed exploration and deep sea mining projects. Papua New Guinea invested millions and millions of dollars into this, but it was not commercially viable. The company went bankrupt and revamped with the same actors, saddling the Papua New Guinea government with debt larger than the country’s annual healthcare budget.

“These kinds of startups are selling, essentially, a bag of false goods,” Justin Alger, a global environmental politics professor at the University of Melbourne, says. The necessity of a moratorium rests not only on ecological unknowns but on the unknown risks to people and inequities that may be created or exacerbated. Until we understand those risks, we should not proceed, especially not on the basis of profit.

The push to mine is supported by a false, dangerous myth of scarcity. “Ultimately, they’re selling snake oil here,” Alger says of deep sea mining companies’ arguments to expedite mining the seabed. Deep sea mining companies frame the need to mine in the deep sea as the way to keep up with the global surge in demand for minerals needed in batteries, electric vehicles, wind turbines and the wider “green” transition. However, this neglects the fact that industries are shifting away from using these minerals, and even though global demand is higher, land-based reserves remain extensive—there is absolutely no need to mine the deep sea.

“Many EV batteries no longer use cobalt or nickel. Iron phosphate batteries don’t require those minerals. We don’t need to mine the deep sea for them.” says Dr. Lisa Levin, a professor at the University of California, San Diego, in the Scripps Institution of Oceanography.

Only a tiny percentage of the deep sea floor has been directly observed and studied. There is even less research on what seabed disturbance could mean for human health. Exploration contracts have been issued to companies for vast swathes of seabed, but our blind spots in regards to the deep sea remain immense. Before we build a more comprehensive understanding of the deep sea and the risks that deep sea mining could pose to ecosystems as well as human health pathways of food and exposure, permitting and pushing for deep sea mining is irresponsible and could very well be disastrous.

Key health concerns include toxic impacts, nutrition and food security, and inequitable exposure to toxins. Mining disturbs seabed sediments and may release heavy metals and chemical mixtures into the water column. These pollutants travel through food webs and may eventually reach humans through seafood consumption or in coastal populations exposed to this polluted water. A 2023 study led by University of Burdwan researcher Sumanta Das found that heavy metal environmental pollution can profoundly harm human health. The authors say that when these heavy metals enter our food chain, they disrupt the food pyramid and pose a threat to human health by causing cancer and liver disease. Copper, cadmium, lead and other rare earth elements can accumulate in body tissues and have been found to have harmful effects on health.

An article by Chris Hauton, a marine biology professor at the University of Southampton,  published in November of 2017 in the journal Frontiers in Marine Science, emphasizes that deep sea organisms live under different pressure, temperature and chemistry than species that reside in shallower waters, making toxicity predictions and subsequently health impacts especially uncertain. Heavy metal exposure accumulates in the human body, interferes with metabolic pathways, and damages cell signaling. It is also linked to neurological damage, kidney and liver impairment, developmental issues in children, and increased cancer risk.

Consider the chain of exposure: mining disturbs seabed minerals; some of those minerals contain toxic metals, including copper, lead, cadmium, and zinc. As the sediments are stirred up, these metals either dissolve or travel through the water as particulates before gathering onto filters, feeding up through small organisms, or accumulating in fish and other seafood, which may end up being consumed by humans, particularly those in coastal and island communities.

Coastal and island communities who depend on seafood and subsequently healthy marine food chains and ecosystems are likely to also be inequitably affected. Deep sea mining would significantly disrupt marine ecosystems, which could result in less abundant or less healthy seafood. According to the Deep Sea Conservation Coalition, scientists are warning that “biodiversity loss would be inevitable, extensive, and most likely irreversible.” Specifically, it could disrupt the deep sea’s ocean carbon cycle and storage.

Along with water pollution, this threatens not just ecological integrity, but the human right to adequate and safe food, water, and health. In a December 2024 report, the Office of the United Nations High Commissioner for Human Rights noted that pollution from deep sea mining “could also have a significant impact on the rights to health, food, water, housing…and self-determination.”

“There’s just no reasonable societal argument in favor of it,” Alger says, citing that the remote and unmonitored nature of these deep sea mining operations would make it “ripe for labor violations which creates all sorts of equity and potential health impacts”.

The operations required to support deep sea mining, including transport, processing, and export may affect worker health, as well as disproportionately expose local communities to byproducts of deep sea mining, such as high levels of noise, chemical spills, and other contaminants or toxins.

Additionally, workers are likely to be exploited in the establishment of deep sea mining operations. The offshore fishing industry already carries documented human rights abuse, such as forced labor. Given that deep sea mining operations are likely to be remote and difficult to monitor, this could replicate or even worsen these conditions with the lack of sufficient regulation on it. Without strong regulations, deep sea mining is a guaranteed health hazard.

Deep sea mining companies are selling a narrative of scarcity, disregarding the predicted and potential impacts that will last for generations after those who make the decision to permit it. Experts heavily discourage permitting any deep sea mining, at least in the status quo.

“I’m not convinced we ever need to mine the deep sea,” says Levin. Essentially, humanity should not gamble with a world it barely understands, not when the consequences are so damaging to human health and global justice. Ancient marine and terrestrial ecosystems are at risk, toxins from mining can harm human communities, and the inequities resulting from it would fall hardest on the exploited communities least able to bear them.

With human and environmental health and human rights hanging in the balance, the only responsible choice is a global moratorium on deep sea mining. Without sufficient research of the impacts, as well as adequate governance to protect the people and the planet, permitting deep sea mining would be irresponsible and reckless. The effects of deep sea mining would last for generations and generations, long after those who permitted it. The importance of safeguarding human and environmental health, as well as the rights of communities who will be impacted most, is paramount—at this pivotal moment, we must make the right decision.