SAN JUAN, Puerto Rico -- An island-wide blackout hit Puerto Rico on Wednesday as the U.S. territory struggles with an increasingly unstable power grid nearly seven months after Hurricane Maria. Officials said it could take 24 to 36 hours to fully restore power to more than 1.4 million customers as outrage grew across the island about the state of Puerto Rico's Electric Power Authority.

"This is too much," said Luis Oscar Rivera, a 42-year-old computer technician who just got normal power back at his house less than two months ago. "It's like the first day of Maria all over again."

Several large power outages have hit Puerto Rico in recent months, but Wednesday was the first time since the Category 4 storm struck on Sept. 20 that the U.S. territory has experienced a full island-wide blackout. It snarled traffic across the island, forced dozens of businesses with no generators to temporarily close and interrupted classes and work.

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The island's international airport switched to a backup generator. No cancellations or delays were immediately reported.

San Juan Mayor Carmen Yulin Cruz said on Twitter that a Wednesday night baseball game between the Cleveland Indians and the Minnesota Twins would still go on.

All emergency systems at Hiram Bithorn Stadium have been tested just now and are fully functional. The game will GO ON. Nothing will stop us pic.twitter.com/u4jpCkjc1Q — Carmen Yulín Cruz (@CarmenYulinCruz) April 18, 2018

CBS News correspondent David Begnaud, who has reported extensively on the island's devastation, reports that the power authority would prioritize restoring electricity to hospitals, the airport and gas stations. Residences would receive the lowest priority.

BREAKING: here’s the priority list that the Puerto Rico power Authority is operating under to restore power as quickly as possible: hospitals

Luis Muñoz Marín Airport

Gas stations

banking centers

shops

residences — David Begnaud (@DavidBegnaud) April 18, 2018

Begnaud reports that the main hospital in San Juan has decided to run on a generator instead of the power grid since the hurricane because the generator was more reliable.

Power company spokeswoman Yohari Molina told The Associated Press that crews were investigating what caused the blackout, saying she had no other details.

Angel Figueroa, president of a union that represents power company workers in Puerto Rico, said it appears that a failure on a main line caused the island's entire electrical grid to shut down to protect itself.

Rivera said he worries that such serious power outages are still occurring as the new Atlantic hurricane season, which starts June 1, approaches.

"If there's a slight storm, we're going to be worse off than we are right now," he said.

Federal officials who testified before Congress last week said they expect to have a plan by June on how to strengthen and stabilize the island's power grid, noting that up to 75 percent of distribution lines were damaged by high winds and flooding.

Meanwhile, the U.S. Army Corps of Engineers, which is overseeing the federal power restoration efforts, said they hope to have the entire island fully energized by May. Some 40,000 power customers still remain without normal electrical service as a result of the hurricane.

The new blackout occurred as Puerto Rico legislators debate a bill that would privatize the island's power company, which is $14 billion in debt and relies on infrastructure nearly three times older than the industry average.