Irving Oil says the company has not yet determined what caused an explosion at Canada's largest Oil refinery in Saint John, New Brunswick.
Officials say the explosion occurred when a diesel treating unit malfunctioned. That's machinery that helps remove sulfur from the diesel.
"We have to understand what caused it and make sure we isolated it before we move forward with anything in the operation," said the company's chief refining supply officer, Kevin Scott, at a press conference.
Two-thousand workers were onsite and many fled following the explosion. Four received minor injuries. The refinery is close to several residential neighborhoods. People living in the area say their homes shook when the explosion occurred.