A Dutch-registered chemical tanker exploded on a canal in Germany early Sunday, killing one person, believed to be the ship's captain, and injuring six, including his wife and two children, police said. The blast came after the barge had discharged its load of naphtha in Essen in northwestern Germany and had anchored for the night in the Rhein-Herne canal, a spokesman for the local police said. The impact of the blast was so powerful that it blew out windows in nearby buildings. German television showed the barge's tanks reduced to twisted metal from the heat but the vessel remained afloat. It was not known what caused the explosion. In the past, barges transporting chemicals down Germany's main river, have collided, run aground and leaked their cargo.