Royal Dutch Shell is carrying out maintenance at its Scotford refinery in Canada, according to a company message on the Alberta Community Update Hotline, a service where firms can give the operational status of their plants.
The message left on Sunday said maintenance was being conducted at one of the units at the plant, but did not specify which unit.
It said the maintenance might result in flaring in the next 72 hours.
The plant has a capacity to process 98,000 barrels of crude a day. (Reporting by Ikuko Kurahone; editing by James Jukwey)