Ford issued a recall notice for 18 F-150 Lightning pickup trucks with defective battery cells, which caused at least one truck to catch fire. The automaker will restart production of the electric truck on Monday, March 13th, with a “clean stock” of battery packs, after a four-week pause of production and shipment to investigate the cause of the defect.

Ford said the “root cause” of the issue was at South Korean battery supplier SK On’s factory in Georgia. In a statement, spokesperson Emma Bergg said that the company was not aware of any reports of accident or injury related to this recall. 

“Together with SK On, we have confirmed the root causes and have implemented quality actions,” Bergg said. “Production is on track to resume Monday with clean stock of battery packs.”

The affected vehicles are either on dealer lots or in customer hands, Bergg confirmed. The automaker has been in close contact with the National Highway Traffic Safety Administration, which is expected to publish the recall notice next week.

Battery fires, while rare, remain a serious concern for EV makers. More data is needed, but researchers have determined that the vast majority of EVs are at low risk for battery fires. Though, when fires do occur, EVs with lithium-ion batteries burn hotter, faster, and require more water to extinguish — a fact that has led some towns to retrain their emergency responders for when such incidents occur.

The most serious incident involved the Chevy Bolt, which was recalled after GM reported at least 19 battery fires due to defective cells from the supplier LG. The automaker was forced to temporarily shut down production after a software fix failed to prevent several more fires. Chevy resumed production last year after installing new battery packs.