A third battery fire involving a Tesla Model S is once again raising questions about the safety of the popular but controversial electric car. After falling as much as 9.0 percent, shares of the company closed down 7.5 percent to $139.77. The latest incident happened Wednesday afternoon in Murfreesboro, , when a Model S drove over a tow hitch in the road that apparently punctured the vehicle's battery compartment.

The driver, Juris Shibayama, was not hurt and was able to get out of his Model S after it caught fire.

A spokeswoman for Tesla said the company has been in touch with the owner. "Our team is on its way to Tennessee to learn more about what happened in the accident. We will provide more information when we're able to do so," said Tesla spokeswoman Liz Jarvis-Shean.

Tesla Model S after it caught fire in Tennessee Source: Tennessee Highway Patrol

NHTSA investigating

With three Model S battery fires happening over the last six weeks, some are wondering if the federal government will open and investigation into the safety of the Tesla vehicles.

(Read more: Tesla Model S fire tests support of investors)

For now, the National Highway Traffic Safety Administration is in the mode of gathering information about the latest fire. "NHTSA will contact the local authorities who are looking into the incident to determine if there are vehicle safety implications that merit agency action," said NHTSA spokeswoman Karen Aldana.



After the first Model S battery fire outside of Seattle, NHTSA said it was monitoring the situation, but was not opening a formal investigation.

That fire was ignited after a Model S drove over a large metal object in the road that punctured the battery compartment. (Read more: Owner of flaming Tesla says he's 'still a big fan')

Following that fire, Tesla CEO Elon Musk said, "For consumers concerned about fire risk, there should be absolutely zero doubt that it is safer to power a car with a battery than a large tank of highly flammable liquid."