Puerto Rico has suffered an island-wide power outage, Puerto Rico's power authority said Wednesday -- nearly seven months after Hurricane Maria destroyed much of the island's infrastructure and its electrical grid.
An excavator operated by a contractor apparently caused the outage, according to the authority, which estimated that power will be restored within 24 to 36 hours.
The utility said its priority was to restore service to hospitals, San Juan's airport, water pumping systems and banks.
Video and photos posted on social media showed rapid transit line workers helping passengers off stalled trains.
Rafael Santiago, an engineer at a plant that makes prosthetic devices, said via Twitter that he and other workers were evacuated after being locked inside for about 20 minutes while electric generators were started.
The massive outage comes less than a week after a fallen tree knocked out service to 870,000 customers, about half the power authority's clients, across a broad swath of the US territory.
At the time, the authority said a major transmission line was damaged while contractors were clearing vegetation.
San Juan Mayor Carmen Yulin Cruz, a frequent critic of recovery efforts since the September hurricane, tweeted Wednesday: "The entire electrical system in Puerto Rico collapses AGAIN! Back to September 20th."
The mayor said backup systems and mobile tower lights will allow Wednesday night's baseball game between the Cleveland Indians and Minnesota Twins to go on as planned at Hiram Bithorn Stadium.
"Nothing will stop us," she tweeted.
"We have backup generators. Game is on as scheduled," Major League Baseball said via email.
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's power outage is now the second-largest blackout in history
Puerto Rico has lost 3.4 billion customer-hours of electricity service due to Maria, according to an analysis released last week by the economic data analytics and policy firm Rhodium Group.
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.
Puerto Rico's power authority faced widespread criticism late last year for signing a $300 million contract to restore power with Whitefish Energy Holdings, a small Montana-based firm with only two employees at the time.
The utility canceled the contract amid public outcry, and its executive director stepped down in November.