AlHijjah 3, 1434, Oct 8, 2013, SPA -- At least seven workers were injured after a gas tank explosion in east China's Shandong Province on Tuesday afternoon, the local government said. The blast occurred at 5:57 p.m. at Boxing Chengli Gas Supply Co., Ltd. in Boxing County, Binzhou City, Xinhua quoted a source with the county government as saying. All the injured have been sent to a hospital for treatment, including two in serious condition. Firefighters were struggling to put out the blaze as of Tuesday evening. The cause of the explosion is unclear.