Tesla Semi Blaze Sparks Debate Over Electric Vehicle Fire Risks

Last month, a Tesla Semi truck caught fire after crashing into a tree on a California highway, resulting in a closure of Interstate 80 for nearly 16 hours. According to the preliminary report from the National Transportation Safety Board (NTSB), it required an astounding 50,000 gallons (approximately 190,000 liters) of water to extinguish the blaze. Additional aerial deployment of fire retardants was necessary to control the situation.

The incident occurred around 3:13 a.m. on August 19, east of Sacramento. While navigating a curve, the Semi veered off the road, hit traffic markers, and collided with a tree. Although the driver was unharmed, he was sent to a hospital as a precaution. The truck’s 900-kilowatt-hour battery erupted into flames, reaching temperatures of 1,000°F (537°C), emitting toxic fumes.

Firefighters faced a formidable challenge, continuously dousing the battery to bring its temperature down to a controllable 100°F target, while waiting for it to deplete its energy. More than 16 hours later, by 7:20 p.m., the interstate was reopened. The NTSB is currently investigating the crash, noting the California Fire Department’s extensive efforts to cool the battery and contain the fire.

The NTSB confirmed that Tesla's Autopilot or Full Self-Driving features were not active during the crash and subsequent fire. Tesla frequently uses these trucks to transport newly produced batteries from their Gigafactory to the Fremont plant. Notably, the truck was not towing a trailer at the time, suggesting the Semi’s battery was the sole source of the fire.

This incident sparked discussions both within governmental bodies and among the public due to its prolonged road closure, hazardous conditions, and toxic smoke emission. It also followed previous incidents involving Tesla’s large-scale batteries igniting in California, raising concerns about electric vehicle fires, particularly given the challenges of extinguishing lithium-ion batteries.

Lithium batteries pose unique fire risks due to their capacity to store substantial energy in compact spaces, resulting in significant heat generation. Experts highlight “thermal runaway,” a feedback loop where heat causes electrolytes to combust, generating more heat and igniting further material. Tesla’s emergency guidelines stipulate using copious amounts of water to cool battery fires, sometimes over 3,000 gallons (11,356 liters) are needed, underscoring the complexity of dealing with such incidents.