An explosion at a Beechcraft aircraft manufacturing plant in Kansas left 15 people injured and caused part of a building to collapse, according to officials. A three-inch nitrogen line ruptured at the Wichita plant, Daniel Wegner, Sedgwick County fire chief, said during a morning news conference. “The plant closed or shut down for the holiday season so the numbers that would have been here, were not, so it was a skeleton crew,” he added. Eleven people were taken to hospitals and four were treated at the scene, according to John Gallagher, Wichita’s county emergency services director. No deaths were reported. Officials are reportedly probing the explosion and monitoring for any residual effects. “Our primary concern is obviously for all of the employees and contractors and visitors on site during this incident,” said Stephanie Harder, spokeswoman for Beechcraft’s parent company, Textron Aviation. “Difficult day. Difficult news,” she added. Harder said that the partially collapsed building contains composite manufacturing and experimental aircraft operations.