Ten of the world’s biggest automakers were sued last week by U.S. consumers who claim they concealed the risks of carbon monoxide poisoning in more than 5 million vehicles equipped with keyless ignitions, leading to 13 deaths, reports The Associated Press. According to the complaint filed in federal court in Los Angeles, carbon monoxide is emitted when drivers leave their vehicles running after taking their electronic key fobs with them, under the mistaken belief that the engines will shut off.