The contact owns a 2019 Ford Expedition. The contact stated that while stopping at a red light, there was a big explosion coming from the seat belt pretensioner that shook the vehicle. Additionally, the seat belt seized, and the air bag warning light was illuminated. The contact sustained whiplash and was treated with anti-inflammatory medication, shots, and muscle relaxers by the doctor. The contact associated the failure with NHTSA Campaign Number: 26V344000 (Seat Belts). The dealer was contacted; however, the vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 136,000.