Tesla battery reignites days after deadly crash: 2 Investigates

2 Investigates has uncovered new information about the deadly Tesla crash in Mountain View earlier this year along with a subsequent warning for all firefighters and all electric vehicles.

The safety alert comes after the March 23 crash when a Tesla Model X slammed into a safety barrier on Highway 101 and erupted in flames.

Firefighters say they put the fire out in 2 minutes but soon discovered the battery fire in the electric vehicle would smolder for hours and reignite even days later.

"The battery began to overheat even though we had already cooled the battery and it continued to reignite," said Mountain View Fire Dept. Chief Juan Diaz

KTVU has obtained a 13-page safety alert written by the Chief Diaz which reveals the dangers firefighters faced including a high-voltage battery they had no way to stop.

"We don't have the tools to deal with a battery that is completely, basically destroyed," said Diaz.

The problem he says was a lithium-ion battery that continued to flow with electricity after it was damaged in the high-speed crash which the NTSB is still investigating.

The other concern firefighters have for electric vehicles is possible electrification of the vehicle.

Most manufacturers have taken action to help first responders by installing a kill switch called a "cut loop" but in the Mountain View incident, that device was destroyed in the crash and firefighters had no way to safely cut off the electricity.

"If it's a rescue, that's where the real risk comes in cause I'm going to be cutting that vehicle, I want to make sure I'm not cutting through an electric cable," said San Jose Fire Dept. Captain Mitch Matlow.

For departments like San Jose Fire, that's not the only danger with electrical vehicles. If a battery is severely damaged and catches fire, that fire can burn hot and long at more than 900 degrees until the battery is exhausted. It's called "thermal runaway."  Auto experts say that's a fancy term for "fire."

In the Tesla crash, firefighters called Tesla engineers who had the tools and training to partially dismantle the battery. But even then, the threat wasn't over.

"In this particular case, 6 days later, the temperature inside those cells increased to the point of ignition. That's why the car reignited," said Chief Diaz. "You have stored energy that is frankly unstable."

The Mountain View Fire Department tells KTVU the Tesla caught fire 3-4 times after the crash. Chief Diaz says it was only after the NTSB and Tesla de-energized the battery 2 weeks later that it was finally safe. In the memo, shared with every fire department in the Bay Area, the fire chief also warns of another dangerous scenario firefighters could face. If a house catches fire with an electric vehicle parked at home, the damaged car battery could reignite later.

"If the battery is damaged, then we're going to have to basically monitor that vehicle for a prolonged (time)--could be days--to make sure it doesn't reignite," said Chief Diaz.

With tens of thousands of new electric cars hitting the market, the threat is greater than ever. The National Auto Alliance says 99,000 all-electric cars were sold in 2017 compared to just 10,000 in 2011. There are 30 electric models now on the market from Tesla's SUV to the Chevy Bolt, even BMW has one.

"Every auto manufacture out there plus new manufactures have got vehicles either just coming on the market or soon to be on the market," said auto expert Michael Coates, who is editor of an online publication "Clean Fleet Report."

"Is it a challenge? Yeah it's a challenge," said Capt. Matlow. "Because every time they come out with a new model car, whether it's electric, gas or diesel or hydrogen or alcohol-powered, it's got something new with it and we have to modify our techniques to deal with that individual hazard."

Most manufacturers including Tesla offer online training and tools for first responders. But the Chinese company BYD that makes electric buses in Lancaster, California, doesn't have that emergency kill switch, the "cut loop", installed at all.

"We have a ways to go in educating firefighters. Especially in areas of the country that they really haven't seen that many electric vehicles yet," said Andrew Klock with the National Fire Protection Association.

Klock started the alternative vehicle training program for the NFPA, one of the main sources for firefighter safety training in the nation. He estimates including his agency's own training program, only 30% of firefighters across the US have been trained at all to handle emergencies involving alternative vehicles.

KTVU contacted more than a dozen fire departments around the Bay Area which said they've had some sort of training on electric vehicles. San Jose Fire says just like hand-on live fire training, every recruit is taught about the hazards of electric vehicles.

"As they become more prevalent, they are getting in more crashes and we have to be aware of that," said Matlow.

In the meantime, Mountain View Fire has banned its crews from touching any damaged batteries "until it is verified that it is 100% de-energized." And with more electric vehicles on the road every year, it's a safety issue that could eventually affect every firefighter in the United States.

"We wanted to share that with the rest of the fire service. Not only with our firefighters in our department but to the rest of the Bay Area Fire departments to know what the challenges that we faced and could potentially face if they encounter a similar situation," said Chief Diaz.

The Mountain View Fire department is considering several changes including creating a specialized team to handle electric vehicle incidents. They also hope get a new device called a DC hot stick, currently in the testing phase, that would allow them to quickly and safely check if an electrical vehicle still has electricity flowing.

KTVU contacted Tesla which stressed the same statistics firefighters also include in their memo, which show electric vehicle fires are less likely to occur than fires in internal combustion vehicles.

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