A fire at a Luma Energy substation in San Juan knocked out power to hundreds of thousands of residents in Puerto Rico on Thursday.

A fire at a Luma Energy substation in San Juan knocked out power to hundreds of thousands of residents in Puerto Rico on Thursday.

Negociado del Cuerpo de Bomberos

A large fire at an electrical substation for Puerto Rico's new electricity provider, Luma Energy, knocked out power for hundreds of thousands of the island's residents Thursday.

At the height of the blackout, nearly 800,000 customers were without power, according to Luma. By midnight, roughly 60,000 customers were still in the dark.

"The fire caused major blackouts across the entire island. The situation is under assessment and work is being done to restore the system," LUMA Energy tweeted.

The fire and blackout were not the only crises facing Luma on Thursday.

Earlier that day, the company announced its client portal and mobile app fell victim to a cyberattack that disrupted customer access to its online services.

The DDoS attack, or distributed denial of service attack, generated 2 million visits per second to the client portal and mobile app, impacting many customers' ability to access account information, according to Luma.

The company said in a statement that it "regrets that its customers experienced the inconvenience the attack may have caused and looks forward to continuing to provide them with an exceptional customer service experience."

It's unclear whether the fire and DDoS attack are connected.

Luma is just 10 days into its new role as the island's power authority. The prior energy provider for the island, Puerto Rico Electric Power Authority, had its own notorious struggles with blackouts, bankruptcy and overall mismanagement in the wake of Hurricane Maria in 2017.

Officials had cautioned residents to be patient in the early days of the transition as Luma inherited frail electric infrastructure. But even before Thursday's blackout, more than 1 million customers lost power just this month alone, not counting those affected by the substation fire, according to The Associated Press.

Puerto Rico's governor calls for an investigation

The fire broke out in a transformer at Luma's Monacillo substation in San Juan, according to the company. Police and fire services went to the scene. No injuries have been reported.

In a message shared on social media, Gov. Pedro Pierluisi referred to the incident as an "explosion."

Pierluisi said both state and federal law enforcement authorities are investigating.

He added, "Whoever is responsible for it will have to answer to the People of Puerto Rico."

FBI San Juan authorities said they are "evaluating" the power outage and encouraged people with information to come forward.

The blackout comes as the island is still working to vaccinate its residents against the coronavirus. Vaccines must be kept at a low temperature to remain viable.

The island's Secretary of Health Carlos Mellado López said in a tweet that hospital services remain uninterrupted and that vaccines are still safe. "Our suppliers have generators and we have over 70 support centers to keep them safe," he wrote.

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