A tanker carrying chemical substances sank off the Yemeni island of Socotra in the Indian Ocean in bad weather Wednesday, DPA QUOTED Yemen's state news agency said as saying. The Panama-flagged vessel, Alexander C, went down amid high seas at around 08:50 am (0550 GMT) north of the Yemeni archipelago of Socotra. Socotra is located some 500 kilometres off the southern coast of Yemen. Nineteen crew members were rescued by another passing Panama- flagged ship, the agency said. Head of Yemen's Maritime Affairs Authority, Ahmed Abdullah, said the vessel disappeared from radar screens after it drifted late on Tuesday. "Contacts are underway with owners of the ship to find out information about the nature of the substances the ship was carrying so as to avoid environmental damages," Abdullah said in a statement.