Up to 2,000 tons of oil have spilled from a major field in northern Russia after workers struggled to contain the leak for two days, officials said.
The accident happened at the Trebs oil field in the Nenets Autonomous District on Friday following work on an exploratory well. The oil had been gushing for nearly two days before the workers finally capped the well Sunday morning, Emergency Ministry officials said.
Vladimir Bezumov, chief of the Russian Environmental Agency in the area, said the weekend spill could have produced between 800 and 2,000 tons and contaminated at least 8,000 square meters (86,100 square. feet) of land. Another 6,000 square meters (64,600 square. feet) of land are believed to have been slightly damaged.
Bezumov said it was too early to speak of the causes of the accident, but he said it was likely a combination of technical issues and human error.
The oil field is developed by a joint venture between Russia's largest private company Lukoil and another Russian oil major Bashneft. It holds some 153 million tons of oil.
Russian environmental officials will be preparing a lawsuit against the oil companies after the clean-up is over, Bezumov said.
The area around the oil field is largely unpopulated but the oil spill has damaged pastures used by local reindeer herdsmen.
Russia has not seen major oil spills for years. But maintenance of pipelines in old fields is poor, and oil leaks from rusty pipes and poorly sealed wells daily, experts say. An AP investigation last year showed that at least 1 percent of Russia's annual oil production, or 5 million tons, is spilled into the environment every year.