Beijing. At least 22 people in China have been killed in an explosion after a leaking oil pipeline caught fire in the city of Qingdao, state media has reported.Xinhua quoted officials who said that workers were trying to repair the pipeline at the time of the explosion.Pictures on social media sites showed shattered concrete slabs and black smoke rising from the scene.More than 100 fire fighters were involved in putting out the fire. The pipeline is owned by Sinopec.The company is China’s largest oil refiner.The authorities have ruled out terrorism but say the incident remains under investigation.Correspondents say that the blast ripped roads apart, turned cars over and sent thick black smoke billowing over the eastern coastal city.Reports say that the number of dead could rise - the number of injured has not yet been confirmed.Because the scene of Friday morning’s explosion is close to the coast, barriers have been erected to stop oil leaking into the sea, reports said.A district government official in Qingdao is quoted as saying that the pipeline ruptured while being repaired, caught fire and exploded.