(Bloomberg) -- BP Plc suffered a serious incident this week at its Rotterdam refinery, Europe’s second-biggest oil-processing plant, according to the Dutch union CNV. 

The complex in the heart of Europe’s oil-trading hub has all but stopped fuels production and employees at the plant who had started work-to-rule action this week have called it off for now. 

According to the Dutch union, the refinery suffered an uncontrolled steam outage, which workers are now trying to resolve. BP didn’t immediately respond to an email asking about the incident.

“Steam is a major energy source for a refinery,” said Steve Sawyer, director of refining at researcher FGE. “If supply is lost then many units if not the whole refinery could shut down.”

BP had been carrying out planned work at the refinery since September. The company failed to return a key gasoline-making unit to operation as it had planned earlier this month, according to a person familiar with the matter. 

Rotterdam is home to Europe’s two biggest refineries, operated by Shell Plc and BP. Shell’s Pernis plant underwent major maintenance earlier in 2022.

(Updates with analyst comment.)

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