The nation's top traffic safety regulator is investigating complaints of fire during crashes in some Ford Motor Co. F-150 Supercrew pickups that have been linked to a seat belt component.
NHTSA said there were five complaints alleging fires following the activation of seat-belt pretensioners made by ZF TRW or Takata Corp. during a crash involving the vehicles.
Pretensioners tighten up any slack in the seat belt webbing in the event of a crash and work in tandem with air bags.
While there were no injuries or fatalities, three of the vehicles were completely destroyed by the fire, NHTSA said.
An estimated 1.4 million vehicles made between 2015 and 2018 could be affected in the investigation, the agency said.