TUCSON, Ariz. (13 News) – A fiery rollover crash on Interstate 10 in Tucson on Wednesday left one person dead and forced firefighters to confront a dangerous challenge — electric vehicle fires.

The Arizona Department of Public Safety is investigating the crash, which happened in the eastbound lanes of I-10 near Valencia Road. DPS said a tractor-trailer carrying vehicles blew a tire, hit a guardrail, and rolled into the median.

At least two of the vehicles on the truck caught fire and burned. The roadway was shut down for hours as crews worked into the night to clear debris and secure the scene.

Tucson Fire Battalion Chief Lyle Steffens said the crew learned the two burning vehicles were EVs, which pose a particular challenge. You can’t just dump water on them like you would for a normal vehicle fire.

“There’s a lot more hazards to our firefights, bystanders, the environment, you name it,” Steffens said.

Fire officials said the biggest concern in EV-related crashes is whether a lithium-ion battery pack is burning or at risk of “thermal runaway,” a chain reaction that can rapidly intensify and become difficult to extinguish. Those fires can also release dangerous chemicals.

“They release really hazardous gases, fluorides, and all sorts of stuff that’s extremely toxic,” Steffens said.

In this case, Tucson Fire said the battery packs did not fully ignite. Steffens noted one vehicle’s battery pack was smoking after being exposed to flames, but it did not escalate into a full lithium-ion battery fire.

“One of them had the battery pack smoking because it was exposed to fire,” Steffens said. “Fortunately, it didn’t have a thermal runaway event, and we didn’t have to fight a true lithium-ion fire.”

Even so, crews used specialized equipment designed for EV incidents, including a fire blanket and a tool firefighters call the “turtle,” which sprays water underneath an electric vehicle to reach the battery area.

“We just overwhelm it with copious amounts of water,” Steffens said.

The TFD said that as more EVs hit the road, crews are using those tools more often, but the threat remains a developing challenge for the fire service.

“We have tools for fighting these. I wouldn’t say that the fire industry or the electric car industry has really solved the issue yet,” Steffens said. “Right now, the fire service is trying to figure out what we do about it.”

DPS said more information about the crash will be released as the investigation continues.

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