The measures Daimler is taking include on site audits with teams of experts and apply to cobalt, as well as other materials used in battery cells. Raw materials such as steel and aluminum are also included. "Mercedes-Benz Cars has made the cobalt supply chain transparent for the award of contracts of battery cells," the company said. — Nima Elbagir, Dominique van Heerden, Anna-Maja Rappard and Alanna Petroff contributed to this article.