As companies and countries withdraw their support for seabed mining, the about-face is raising broader questions about how metals used in battery production are sourced and the scale of the associated environmental costs. The sourcing of nickel particularly has been in the spotlight. Last week, A.P. Moller-Maersk became the latest company to drop its investment in The Metals Company, a prospective seabed miner based in Vancouver, British Columbia. Lockheed Martin and Norway’s Storebrand also have recently sold their interests in deep-sea mining companies. Others including German luxury carmaker BMW have said that, given environmental concerns, they won’t use battery metals...