Update: Power Restored in Puerto Rico

Update: Power was restored to 97 percent of Puerto Rico Thursday afternoon, about a day after the excavator incident below shut down the island's entire grid. Approximately 40,000 people still lack regular electric service and the U.S. Army Corps of Engineers expects power for those parts of the system to be restored by late May, weeks before the 2018 hurricane season begins in June, AP reports.

Puerto Rico's power authority said the U.S. territory is in the midst of an island-wide power outage. The cause of the blackout is unclear but the Associated Press quoted officials saying an excavator accidentally downed a transmission line. The power authority estimated it may take 24 to 36 hours for power to be restored, CNN reported.

This blackout is the first island-wide outage since Hurricane Maria destroyed much of the island's infrastructure, including its electrical grid, nearly seven months ago. Partial outages have hit the island several times in recent months. Last week, a fallen tree knocked out power to 870,000 customers across much of the island.

AP reported that traffic is snarled and businesses have been forced to close throughout the island while hospitals and the main international airport are running on standby generators.

Puerto Rico, home to more than 3 million US citizens, has grappled with widespread power outages for months since Hurricane Maria devastated the Caribbean island.

Puerto Rico, home to more than 3 million U.S. citizens, has lost 3.4 billion customer-hours of electricity service due to Maria, according to an analysis released last week by the Rhodium Group, an economic data analytics and policy firm.

It's the largest blackout in US history and the second largest in the world -- after the outage caused when Typhoon Haiyan tore through the Philippines in 2013, killing more than 6,000 people.