An explosion at a chemical plant in southwest China left 19 dead and injured another 12, authorities said Friday. The blast occurred at 6:30 pm Thursday night at an industrial park in Sichuan provinces Yibin city, according to a statement on the website of the local work safety administration. The injured had been taken to hospital and were in stable condition, county officials said, adding that the resulting fire had been put out. Photos on a local news site showed what appeared to be the burned out shell of a building surrounded by rubble. The company that owns the building where the fire occurred is a chemical manufacturer named Hengda, according to the official Xinhua news service. The cause of the blast is not yet known. The plant has three production lines, making 300 tons per year (tpy) of benzoic acid, which is used in food preservatives, and 2,000 tpy of 5-nitroisophthalic acid, for medicines and dyes, the regional environmental protection bureau says. China has been rocked by several industrial accidents in recent years.