Five people have been injured, one critically, in an explosion at a tank car maintenance facility in the Canadian city of Sarnia, Ontario.<br /><br />Police in the city, home to several oil refineries and petrochemical plants, said on Twitter the fire at the Veolia Environmental Services site had been quickly brought under control.<br /><br />It said one of the five injured was being transferred to a hospital in London, Ontario.<br /><br />Sarnia Mayor Mike Bradley said the cause of the blast was unclear.
