A fire at a power plant in Puerto Rico on Wednesday has left an estimated 1.5 million people without electricity, NBC reported.

The fire and power outage have affected towns throughout the island: Bayamón, Carolina, Caguas, Fajardo, Mayagüez, Guaynabo, Río Grande, Humacao, Dorado, Cayey, Isabela, Guayama and San Juan.

In addition, traffic lights were off on the island, a city train stopped functioning in the main town of San Juan.

“Right now there is an investigation and there will be updates later on,” the statement of the Puerto Rico Authority of Electric Energy said.

Firefighters are working at the site.