Yet another setback strikes Puerto Rico more than six months after Hurricane Maria ravaged the region and destroyed its power grid. On Wednesday, a faulty transmission line caused an island-wide blackout , and it could take up to 36 hours to restore power. The Puerto Rico Electric Power Authority said the San Juan airport, hospitals and banks will get priority before power is back on in homes and businesses. Meanwhile, a new hurricane season starts in June and is forecast to be harsh. Again.