MONTREAL, Canada (AFP) — An oil platform off the Canadian island of Newfoundland spilled nearly 3,200 gallons of an oil-water mix into the Atlantic Ocean, and efforts were underway to minimize the environmental impact, ExxonMobil said Thursday.

The spill occurred a day earlier during “routine activities related to removing water” from a platform storage cell, the American oil giant said earlier.

“The estimated volume of oil released from the Hibernia platform was 75 barrels of oil, equivalent to approximately 12,000 litres (3,170 gallons),” according to aerial surveillance, the Hibernia Management and Development Company (HMDC) said in a statement released by ExxonMobil.

That area of the North Atlantic is rich in marine life, including species of whales, but HMDC said “no wildlife has been observed in the area” by specialists who were sent out.

“We’re disappointed the discharge occurred, but we are working diligently to minimize impacts on the environment,” the statement quoted Scott Sandlin, HMDC’s president, as saying.

On Wednesday the company said it temporarily shut the oil platform after discovering the oil-water spill into the ocean.

It was using a range of clean-up measures including a boom-type system deployed over the side of a vessel, assisted by a skimmer.

HMDC said it was monitoring a sheen on the ocean surface with an approximate radius of three nautical miles (3.5 miles, 5.6 kilometres), about 204 miles east of St John’s Newfoundland.

“Vessels have been tasked with monitoring and clean-up of the sheen and requests that all mariners keep a 10 nautical mile berth from this area,” it said.

Hibernia — which opened for production in 1997 and is located about 196 miles east of St John’s — is jointly owned by Chevron, Suncor and Equinor (formerly Statoil) in addition to ExxonMobil, which holds the majority share.

The oil deposit below Hibernia — accessed via underwater drilling — is estimated to contain more than 1.2 billion barrels of oil.