An anonymous reader writes: Amnesty International has accused Apple, Samsung, Sony, and other tech companies of failing to do basic checks to ensure minerals used in their products are not mined by children. A new report explains how cobalt is harvested from mines by children as young as seven years old. The cobalt then ends up in lithium-ion batteries sold to device-makers throughout the world. The list of companies who use these batteries also includes Daimler, Dell, HP, Huawei, Lenovo, LG, Microsoft, Vodafone, Volkswagen, and ZTE. Amnesty International notes that half the world's cobalt comes from the Democratic Republic of the Congo, where many mining operations have terrible track records for accidents and concern for workers' welfare. They say, "the vast majority of miners spend long hours every day working with cobalt without the most basic of protective equipment, such as gloves, work clothes or facemasks to protect them from lung or skin disease." According to UNICEF, about 40,000 kids worked in mines across southern DRC in 2014.