NTSB investigating fiery Tesla Semi EV crash on Interstate 80 in Northern California

The National Transportation Safety Board has launched an investigation into a fiery crash on Monday that led the batteries on a Tesla big-rig truck to burn for four hours along Interstate 80 in Northern California’s Sierra Nevada mountains.

The NTSB on Wednesday afternoon announced that it had opened its safety investigation, in coordination with the California Highway Patrol, of the crash and fire of the Tesla electric truck near Emigrant Gap in Placer County.

Sarah Taylor Sulick, an NTSB spokeswoman, said on Thursday that investigators from the agency’s Office of Highway Safety were expected to travel to Emigrant Gap to examine the wreckage and gather details about the events leading up to the crash and the subsequent response to the truck fire.

The crash occurred about 3:15 a.m. Monday, when the electric vehicle heading east on I-80 at the Laing Road offramp crashed onto the right shoulder and into trees, according to the CHP’s incident log.

Sulick said preliminary information indicates the Tesla truck went off the freeway, struck trees and caught fire. She also said the truck’s batteries continued to burn for four hours.

“The NTSB is investigating this event due to its interest in the fire risks associated with lithium-ion batteries,” Sulick said in a written statement.

Tesla’s news media relations officials did not immediately respond Thursday to The Sacramento Bee’s request for a comment.

Officer Jason Lyman, a spokesman for the CHP’s Gold Run office, said Monday that only one vehicle was involved in the crash, and the truck driver was not injured. Lyman said the white Tesla Semi truck was without a trailer when it was headed uphill west of Yuba Gap. But he also said investigators were still trying to piece together what led the Tesla to leave the road.

The fire, sparked by the batteries of the roughly 13-ton vehicle, produced “quite the plume of smoke” early on as firefighters rushed in to fight the flames with chemicals, Lyman said. The fire was still smoldering nearly six hours after the crash, according to the CHP spokesman.

He said authorities had to create a half-mile buffer zone around the truck fire to keep “toxic” fumes from injuring bystanders and passing drivers. Firefighters from Cal Fire’s Nevada-Yuba-Placer unit battled the flames using masks and breathing apparatus.

I-80 was closed in both directions at 5:30 a.m. Monday. Caltrans announced shortly before 2 p.m. that firefighting planes from Cal Fire performed aerial drops to keep the fire under control as crews continued to cordon off the burn area.

After working on the fire for more than 16 hours, the CHP announced on Monday evening that I-80 was reopened in both directions to vehicle traffic.

In November 2020, the NTSB published a report based on its investigation of three electric vehicle crashes resulting in fires involving an electric vehicle. The NTSB said these fires illustrated the risks to emergency responders posed by the vehicles’ high-voltage lithium-ion batteries.

“Fires in electric vehicles powered by high-voltage lithium-ion batteries pose the risk of electric shock to emergency responders from exposure to the high-voltage components of a damaged lithium-ion battery,” NTSB officials wrote in a summary of the report. “A further risk is that damaged cells in the battery can experience uncontrolled increases in temperature and pressure (thermal runaway), which can lead to hazards such as battery reignition/fire.”

NTSB officials also said the risks of electric shock and battery reignition of the fire arise from the “stranded” energy that remains in a damaged battery.