The Hibernia oil platform in Canada was shut after a leakage of drilling and production fluids, the Hibernia Management and Development Co (HMDC) said late Monday.
Hibernia sits roughly 315 km (200 miles) east of St. John's, Newfoundland and Labrador. ExxonMobil owns the largest stake in the oil platform, followed by Chevron Canada and Suncor Energy Inc.
"Water sampling late on July 19, during drill well flow back operations, indicated an exceedance on the produced water discharge," HDMC said.
The sheen was observed 2.5 kilometers (1.55 miles) from the 220,000-barrel-per-day platform and all personnel are safe, the company said, adding that the Canada-Newfoundland and Labrador Offshore Petroleum Board has been notified.
(Reporting by K. Sathya Narayanan in Bengaluru, Editing by Sherry Jacob-Phillips)