A Maltese-registered tanker carrying 8,000 tons of potentially explosive sulphuric acid sank in the Bay of Biscay on Tuesday, French maritime authorities said. The 23 crew were picked up by ships and were safe, they said. A spokesman for France's Atlantic Surveillance and Rescue Center said there was a slight risk that the sulphuric acid would explode on contact with water. "The motor tanker Balu is reported sunk in international waters this morning about 130 miles (209 km) north of (the Spanish port of) La Coruna... while facing severe weather conditions," read a statement from Traschimar. French maritime authorities said earlier that it was not clear why the 5,795-ton tanker had sunk, and described weather conditions as "normal" for the time of year.