Tesla Motors Inc. cars have caught fire after collisions more often than gasoline-powered vehicles, according to a Massachusetts Institute of Technology report rebutting assertions by Elon Musk, the electric-car maker’s chief executive officer.
Because only 4 percent of vehicle fires are caused by collisions, Tesla’s Model S sedan, with a rechargeable lithium-ion battery, is statistically more likely to catch fire in those incidents than cars with gasoline tanks, wrote Kevin Bullis, senior editor for energy for MIT Technology Review.
One in 32,603 registered vehicles catches fire compared with 1 in 6,333 of the Model S, Bullis said in a blog post today, using U.S. government data. Fewer than 1 percent of registered vehicles are plug-in electrics.
“Based on the limited data, Musk probably isn’t justified in making a strong claim that the Model S is less likely to catch fire,” Bullis wrote. “It’s also probably too early to make the reverse claim -- that the Model S is more likely to catch on fire.”
Musk is basing his defense of the Model S, under investigation by auto-safety regulators following two U.S. car fires since Oct. 1, on the fact that gasoline cars catch fire more often than electric cars. The MIT report, according to Bullis, narrows it to a direct comparison of fires caused by collisions.
Data showing a higher incidence of fire in Teslas may limit the effectiveness of his message as the company, based in Palo Alto, California, seeks to avoid a recall of the vehicle it has called the safest U.S. car.
The Model S, Tesla’s only vehicle, sells for $70,000 to more than $100,000 and was developed with the help of a U.S. loan. It received the highest possible crash-test ratings from U.S. regulators this year as well as the highest scores among all vehicles for performance and customer satisfaction from Consumer Reports magazine.
George Blankenship, who was vice president of sales, has left the company, the San Jose Mercury News reported today.
Tesla shares rose less than 1 percent to $122.10 today at 4 p.m. in New York trading. The shares have fallen 37 percent since their peak on Sept. 30, the day before the first Model S fire.
Liz Jarvis-Shean, a Tesla spokeswoman, didn’t immediately respond to an e-mail seeking comment.
Musk’s decision to emphasize the rarity of two fires with no injuries among his Model S electric cars is similar to Ford Motor Co.’s decision to wait to recall models with faulty ignition switches until fires were more prevalent, said Clarence Ditlow, executive director of the Center for Auto Safety, a Washington-based advocacy group.
Ford ultimately recalled 15 million vehicles for the fault in a series of actions from 1999 to 2007.
“Tesla is making a mistake with this because you don’t need injuries to have a defect, and unreasonable risk,” Ditlow said. “Just doing a back of the envelope calculation, the incidence rate on the Tesla Model S based on registered vehicle years is 63 times higher than the recalled Fords.”
Of all vehicle fires in the U.S. from 2008 to 2010, only 1.7 percent originated in the fuel tank or fuel line, according to a January report from the Federal Emergency Management Agency’s U.S. Fire Administration National Fire Data Center. Less than 1 percent of all highway vehicle fires were fatal.
An average of 209 people were killed and 764 injured among 152,300 passenger car fires annually from 2006 to 2010, according to a study released last year by the National Fire Protection Association in Quincy, Massachusetts.
Of the deaths, 60 percent were from crashes and 12 percent were from mechanical or electrical failure, according to the NFPA report.
Four percent, or 5,700 of the fires resulted from collisions yet represented 60 percent of the deaths, or 125, on average each year from from 2006 to 2010.
“There’s still a risk associated with conventional vehicle fires,” Marty Ahrens, the author of the NFPA report, said in an interview. “One of the things that we do need to always watch is that people look for something that is this new thing and forget about all the risks that are in the current environment.”
The data are not yet specific enough to determine if any of the fire deaths in passenger vehicles are related to alternative technology, she said.
“We obviously have an issue with vehicle fires and vehicle fire deaths,” said Ahrens, who is the senior manager of fire analysis services at the National Fire Protection Association, which advocates for fire safety via codes and standards. “We should not be surprised to see additional vehicles fires with new technology.”
About 69 percent of automobile fires were caused by mechanical or electrical failure or malfunction compared with 4 percent caused by a collision or rollover, according to the data.
The smaller number of fires caused by collisions resulted in an average of 125 deaths per year out of the 209 total because of the severity of the crashes, she said. By comparison, about 33,561 people died in highway deaths in the U.S. last year, according to the National Highway Traffic Safety Administration.
“NHTSA does not believe electric vehicles pose a greater risk of fire than gasoline-powered vehicles, but the agency recognize that the different types of vehicles may pose different kinds of fire risks,” Nathan Naylor, a NHTSA spokesman, said in an e-mail. “This is one reason that NHTSA issued guidance for emergency responders and others concerning potential issues” when electric vehicles are involved in crashes.