Suncor says there was a leak at its Sarnia refinery on Friday morning.
The company said it was detected in underground piping running between a solvent tank and the rail loading rack.
The leak, which was contained on-site, was immediately isolated and is no longer active. Refinery fence line monitoring did not detect any odours or readings for volatile organic compounds.
Suncor said efforts are underway to clean-up the material and notification has been provided to the Spills Action Centre and CAER.
