- About 12 hours into the blackout, power had been restored to just over 130,000 customers
- Public schools canceled classes and government employees were asked to work limited hours
(CNN)Puerto Rico has gone dark.
A power outage on the island has left nearly 1.5 million people without power, according to a statement from the government-run electric company AEE.
The blackout is affecting most of the US territory, causing traffic jams and forcing business closures.
About 12 hours into the blackout power had been restored to just over 130,000 customers, Puerto Rico Gov. Alejandro García Padilla said Thursday morning.
That still left about a third of the population without power.
AEE said the blackout began late Wednesday after a fire at its Aguirre power plant.
Fire Chief Angel Crespo said a power switch got overheated, causing a 2,000-gallon mineral oil tank to explode. Fire spread over a 3-acre area before firefighters managed to put it out.
The power outage also shut off water service for about 340,000 people, the governor said.
Public schools canceled classes and government employees were asked to work limited hours. Many private institutions followed suit.
García Padilla said they expect to get power back up for most people sometime this afternoon. However, he made it clear it wasn't a promise and the timeline could change.
"I don't want to give false expectations. Lots of setbacks may occur," he said.
Telecommunications services are working normally, according to the governor.
The Luis Muñoz Marin International Airport continues to operate, García Padilla said, but he asked passengers to get there earlier than usual. Passengers are being checked in manually to preserve power.