A large-scale oil spill, believed to be from a tanker struck by the US military, doubled in size between Wednesday and Thursday, endangering two protected areas off Oman and Iran, said Nina Noelle of Greenpeace Germany. The tanker RIESCO was one of four attacked Tuesday in the Gulf of Oman. A fifth was destroyed in the Strait of Hormuz off Iran’s Kharg island. The visible area of pollution measured about 400 square kilometers (154 square miles) on Thursday, Noelle said. Satellite images reviewed