One person was killed and three others were injured in an explosion that occurred Tuesday morning at a university in Nanjing, capital of east China's Jiangsu Province, university sources said according to dpa. The explosion occurred at 9 a.m. in a disused laboratory at the Nanjing University of Science and Technology, destroying the lab and shattering windows in nearby homes, Xinhua quoted the municipal fire department as saying. The university said the explosion occurred while the lab was being demolished by a construction crew. Rescue efforts are under way and the cause of the explosion is being investigated, local police said.