A Greek tanker abandoned after Yemen’s Houthi rebels struck it in August, threatening environmental disaster with more than a million barrels of oil on board, has been towed to safety, EU maritime safety body Aspides said Monday. Aspides said “private actors” had completed the challenging salvage operation of the Greek-flagged vessel Sounion but added it would continue to monitor the situation. Had the vessel broken up or exploded, it could have caused an oil spill four times larger than that caused by the Exxon Valdez in 1989 off Alaska, experts had warned. The Sounion, carrying around 150,00…