The Canada-Newfoundland and Labrador Offshore Petroleum Board says the Hibernia Management and Development Company (HMDC) reported Friday that the leak happened from Dec. 27 to Jan. 1.
Company spokeswoman Margot Bruce-O'Connell said in an emailed statement that the operator is still looking into the cause.
"The release is from the Hibernia platform's north loading system," she said of transmission pipelines that offload oil to tankers for transport.
"HMDC regrets this discharge and is committed to operating in an environmentally responsible manner. Personnel on the standby vessel have been monitoring the area and have not observed any impact on birds or marine life."
A leak of about 10 litres of crude oil was first reported to the regulator Dec. 18. The board said last month that a sheen was spotted on the water more than a week later and a remotely operated vehicle confirmed Dec. 30 that a hose-end valve was seeping.
At the time, the company said it had suspended offloading to tankers, cut back production rates and would fix the problem as soon as weather allowed.
Hibernia has two offshore loading systems for hydrocarbons, one of which is working normally, and the platform is back to regular production, Bruce-O'Connell said Friday.
The board says it will launch a full investigation into the spill and review the methods used by the operator to estimate the amount of oil that leaked.
ExxonMobil Canada, Chevron Canada and Suncor (TSX:SU) are the largest shareholders in Hibernia.
Previous spills in Newfoundland's offshore sector include 165,000 litres of crude oil from the Terra Nova production vessel in November 2004, then operated by Petro-Canada, and 4,470 litres of crude oil from Husky Energy's SeaRose production vessel in September 2008.
Petro-Canada was later fined $290,000 for the spill that was traced to a test separator that was supposed to divide oil and water.
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