Following the third fire in barely six weeks, the National Highway Traffic Safety Administration has opened a formal investigation of the Tesla Model S electric vehicle.
Two of the fires occurred after the cars struck large pieces of road debris, penetrating their battery compartments and apparently causing short circuits. A third blaze followed a high-speed crash. In all instances, drivers were able to escape the vehicles without injury.
But concerns about the fires have contributed to a recent run on start-up carmaker Tesla’s once high-flying stock.
A total of 13,000 of the Model S battery cars sold in the U.S. are directly covered by the investigation though if NHTSA were to order a recall or some other action it might also impact an additional 6,000 vehicles shipped abroad since sales of the Model S began in July 2012.