The CEO of electric car company Tesla Motors Inc. says a vehicle that caught fire near Seattle this week was apparently impaled by a metal object. Elon Musk wrote in a blog post Friday that fires are more common in conventional gas-powered vehicles and that it's safer to power a car with a battery. Musk says a curved metal object that fell of a tractor-trailer was apparently to blame for the fire Tuesday. He says the object's shape led to a powerful hit on the underside of the Tesla Model S, punching a 3-inch hole through an armor plate that protects the bottom of the vehicle. The company says the car properly contained the blaze.