General Motors will hold its annual shareholder meeting on Tuesday. One item up for discussion: whether the automaker should take a stand on the use of metals mined from the seafloor. Tesla faces the same question at its shareholder meeting later this month.

Demand for some metals in the auto industry is expected to grow due to electrification. But firms are also under pressure from shareholders to follow environment, social and governance, or ESG, principles. And there’s no one playbook carmakers are following to source those materials ethically.

Carmakers are facing more and more scrutiny about where the metals they use are coming from. Gerard Barron, CEO of The Metals Company, has one solution: “Here we are with an alternative supply, 1,000 miles from the nearest living human, 4,000 meters below sea.”

His firm is looking to collect millions of tons of cobalt and nickel ore from the bottom of the Pacific Ocean — far from any rainforests or drinking water — then sell that metal to car companies. But this type of extraction has never been done at a commercial scale.

It could permanently damage ocean habitat, argues Andy Whitmore, finance advocacy officer the nonprofit Deep Sea Mining Campaign.

“Deep sea mining itself is an industry that has a large number of potential risks; some of those are reputational risks,” he said.

Reputational risks that some carmakers don’t want to take on. BMW, Volvo and Volkswagen have all said they won’t use ocean-mined metals. GM’s board of directors says there’s no need to take a stand, because the company’s not currently using those metals.