Accident and fire involving a Tesla semi-trailer on I-80 are being investigated by the government

An accident and subsequent battery fire earlier this week involving one of Tesla's semi-trailers that closed I-80 in both directions for nearly an entire day is now being investigated by the National Transportation Safety Board.

“The NTSB, in coordination with the California Highway Patrol, has opened a safety investigation into the August 19 crash and fire involving a Tesla electric semi-trailer truck on Interstate 80 near Emigrant Gap, California,” the agency tweeted Wednesday evening.

The truck fire started around 3 a.m. Monday when the truck went off the road on eastbound I-80 and struck some trees near Emigrant Gap. The truck's lithium-ion battery, which is about 10 times the size of a regular Tesla battery, caught fire, creating a hazardous materials situation that lasted 16 hours.

As KPIX reported, firefighters had to let the battery fire burn out because it cannot simply be sprayed with water. It created a lot of toxic fumes that forced I-80 to be closed in both directions.

“The water you use to put out a fire builds up toxic chemicals. It creates sulfuric acid and hydrochloric acid,” Dylan Khoo, an electric vehicle industry analyst, told KPIX.

Khoo further explained that the size of the truck battery makes this situation more difficult than if a regular, car-sized electric vehicle battery caught fire. “This battery will release a lot more toxic gases. It will burn for a lot longer. It is generally much more difficult to extinguish.”

The westbound lanes of I-80 finally reopened Monday evening, about 13 hours after the fire broke out, while the eastbound lanes did not reopen until around 7 p.m.

Many car and truck drivers were held up by the closure of the motorway or had to deal with major diversions.

The fire came just three weeks after a similar fire involving lithium-ion batteries occurred in a truck accident in San Bernardino County. That incident occurred on I-15 in Baker, California, and led to a two-day closure of the highway as the fire burned itself out. When attempts were made to push the burning battery substance into the desert, it reignited and burned even hotter. Many drivers got stuck, ran out of gas, and a detour onto I-40 led to a 50-mile traffic jam, Fox5 Vegas reported.

The truck in this fire was not an electric truck, but was carrying a load of lithium-ion batteries for a solar farm in Wisconsin.

The two incidents combined prompted Republican lawmakers in Sacramento to call on Governor Gavin Newsom to delay his Advanced Clean Fleets mandate, which would require all medium- to heavy-duty trucks in California to convert to zero-emission vehicles by 2045.