At least 22 people were killed after a leaking pipeline caught fire and exploded on Friday in the coastal city of Qingdao, east China's Shandong Province, state-run Xinhua News Agency reported. The accident happened around 10:30 a.m. (0230 GMT) in Huangdao District, the report said, adding that workers were repairing the petroleum pipeline, which was leaking oil at around 3 a.m., Qingdao government's publicity office, said, according to the report. The pipeline is owned by Sinopec, China's largest oil refiner. Pieces of cement and debris were scattered around the explosion site which is close to the coast. Photographs posted on Sina Weibo, China's Twitter, showed the blast had caused a large trench in the ground and car windows nearby were cracked. Environmental monitoring showed that the concentration of toxic materials in the air is under the national standard, and the local government has told citizens to stay calm.