It took hours for firefighters to put out the fire.
"A fire broke out at Rivian’s assembly plant in Normal, Illinois, last weekend due to a faulty battery pack. The town of Normal posted the news on its official government website, and it was brought to our attention via Automotive News’ report of the fire.

The fire was contained to a single faulty battery pack that was being tested in Rivian’s battery testing area of the plant. The battery was going through thermal runaway when firefighters arrived. Because of this, the firefighters kept applying cold water to the battery long after the initial flames were extinguished to keep it cool and prevent it from catching fire again. Firefighters from Bloomington, Indiana, were called in to assist the Normal firefighters at the large facility. After the fire was deemed fully out, they began ventilating the building to make it safe and operable once again.

Automotive News received an explanation from Rivian on the incident, stating that the battery pack had already been deemed faulty prior to the fire.

“No injuries occurred during the event, and production in the area has restarted," the spokesperson told AN. "Every one of our batteries undergoes a rigorous and comprehensive testing regime before being certified for installation in our vehicles."

The incident was a rather long one. Normal firefighters say they arrived at 10:38 a.m., and the extinguished battery was finally turned back over to Rivian at 2 p.m. The cause of the fire is still under investigation, and damage was limited to just the battery pack, battery pack carrier and test booth equipment."