DETROIT (AP) — A Tesla Model S electric car caught fire this week after hitting road debris on a Tennessee freeway, the third fire in a Model S in the past five weeks.
The blaze on Wednesday afternoon near Smyrna, Tenn., engulfed the front of the car. A spokeswoman for the Tennessee Highway Patrol says the Model S ran over a tow hitch, which hit the undercarriage of the car, causing an electrical fire.
It's the second Model S blaze involving road debris. In early October, a driver near Seattle hit debris that pierced a shield and the battery pack, causing a fire. In the other fire, a driver in Mexico crashed into a concrete wall and a tree at a high speed.
Shares of the carmaker, based in Palo Alto, Calif., fell 7.5 percent to $139.77 on Thursday. That's on top of Wednesday's plunge of 14.5 percent, after concerns about a battery shortage, as well as the costs Tesla will incur as it builds more cars, spooked some investors. The shares are still up 312 percent this year.
The Model S has as a large battery pack under the passenger compartment, protected by a quarter-inch-thick metal shield. Experts say that if debris punctures the shield and damages the battery, it can cause shorts and arcing that can touch off fires.
The National Highway Traffic Safety Administration, the U.S. government's auto safety watchdog, says the agency will contact Tennessee authorities to determine if there are safety problems that need further action. NHTSA decided last month not to investigate the Seattle-area fire, saying there was no evidence it was caused by a safety defect.
The driver in Tennessee was able to pull onto an emergency lane and escape. Tesla said it has sent a team to investigate.
Company spokeswoman Liz Jarvis-Shean says the fire was not spontaneous. She says Tesla contacted the driver, who believes the car saved his life. Tesla CEO Elon Musk has said that the design of the Model S is safer than that of a car with a conventional fuel tank.