Production was shut down for a second day at the 220,000-barrel-per-day Hibernia oil platform off the coast of Atlantic Canada as crews worked to clean up an oil spill into the ocean, Hibernia’s largest shareholder Exxon Mobil Corp. said on July 18.

A sheen was first spotted on the water near the platform on July 17 and production was halted to deal with the spill, a mix of oil and water, estimated to total about 75 barrels.

Exxon Mobil spokeswoman Lynn Evans said the company could not say how long production would be shut down.

Investigations found the release was discharged during “routine activities related to removing water from one of the storage cells,” Hibernia Management and Development Co. Ltd. (HMDC), which operates the platform, said in a statement.

A boom-type system is being used collect oil from the water, added HMDC, which is also deploying surveillance flights and a tracking buoy. All workers on the platform are safe and no wildlife has been observed in the area. An investigation into the spill is continuing.

“We’re disappointed the discharge occurred, but we are working diligently to minimize impacts on the environment,” HMDC President Scott Sandlin said.

Hibernia has been producing oil since 1997 and sits roughly 315 km (200 miles) east of St. John’s, Newfoundland and Labrador. Exxon Mobil owns the largest stake in the project, followed by Chevron Canada and Suncor Energy Inc.