Humberto Reyes, the refinery's public affairs representative, told the state-run Bolivarian News Agency that the cause of the fire Sunday evening was under investigation. No injuries were reported, he said.
The fire forced the refinery to shut down one of its processing units, Oil Minister Rafael Ramirez told reporters. He said it wasn't immediately clear how long the unit would be out of service.
Cardon is part of the Paraguana refining complex, which has an output capacity of 940,000 barrels of crude oil per day. The complex, which also includes the giant Amuay refinery, normally produces around 700,000 barrels of oil per day, the AP reports.