DUBAI, United Arab Emirates (AP) — An explosion tore through Qatar’s key natural gas export terminal Sunday night as workers tried to resume operations there after Iran bombed it during the war, causing a fire that hurt at least 54 people as another 18 were still missing hours later.

The blast at the Ras Laffan industrial area could cause further chaos in global energy markets, particularly as Qatar remains one of the world’s top natural gas producers. Qatar shut down its production after Iran’s chokehold on the Strait of Hormuz meant it couldn’t get shipments out to its clients.

With Iran loosening its grip on the strait as negotiations continue over a permanent end to the war, Qatar began work to try to restart its export terminal. On Sunday night, that work sparked an explosion and fire at the Barzan gas supply facility, the state-run firm QatarEnergy said.

The scale of the damage remains unknown after the blast, with officials initially saying only a few people had been hurt. But hours later, Qatar’s Interior Ministry offered the far-greater casualty figures.

The Barzan plant had a capacity of almost 1.4 billion standard cubic feet of sales gas per day, which Qatar used primarily for local electricity generation and to power its crucial water desalination plants in the desert reaches of the Arabian Peninsula.

Qatar owns nearly all of the plant, with a small share also held by ExxonMobil. The oil company did not immediately respond to a request for comment.

In March, an Iranian missile hit Ras Laffan, sparking a fire that caused “extensive” damage before it was extinguished, authorities said. Qatar had already halted production there because of Iranian attacks.

Qatar shares its massive offshore natural gas field in the Persian Gulf with Iran. That natural gas production has made Qatar wealthy. It has used that money to raise its profile worldwide through hosting the 2022 FIFA World Cup, creating the Al Jazeera news network and funding its work as an international mediator, including the talks in Switzerland between Iran and the United States.

Jon Gambrell, The Associated Press