Tesla semi-truck fire that shut down I-80 took 50,000 gallons of water to put out, NTSB says

The initial findings have been released from the National Transportation Safety Board investigation into August's Tesla semi-truck fire that shut down Interstate 80 for hours .

As detailed by investigators, the battery-powered truck crashed near Emigrant Gap a little after 3 a.m. on Aug. 19.

NTSB officials say the truck was being operated by a Tesla employee and was heading from Livermore to a Tesla facility in Sparks, Nev.

Investigators say the truck first hit a traffic delineator, then a tree, before continuing down a slope and coming to rest against more trees. As the report notes, the truck's lithium-ion batteries ignited after the crash.

Notably, the report did not come to a conclusion about what started the fire.

It took about 50,000 gallons of water to put out the fire, investigators say. Cal Fire aircraft also dropped fire retardant around the area as a precaution against the flames from spreading to wildland.

I-80 ended up being closed for more than 12 hours due to the fire. The report states that the extended closure was also in part to make sure that the batteries were at a safe enough temperature for recovery operations to start.

Recovery crews took the truck to an undisclosed open-air facility to be monitored for possible reignition for 24 hours. The report states that the batteries did not reignite during this observation period.

The truck driver was not hurt in the crash. NTSB noted that, while the truck was equipped with Advanced Driver Assistance Systems, the system was not operational at the time and couldn't be engaged.

The NTSB is continuing to investigate the crash. The agency expects to issue safety recommendations that should help prevent a similar event.