Bashneft has finished cleaning up pollution from a well-head spill at its Trebs oil field, the company said.
In a statement published on its website Wednesday, the company claimed to have completed the clean-up operation "ahead of schedule," including cleaning up the area near the well, using absorbents to remove residual contamination, and subsequent rehabilitation of affected land.
An estimated 2,200 tons of oil escaped when an unsealed well head at the oil field in the Yamal-Nenets autonomous district burst in April, sending a 25-meter fountain of oil gushing into the air and bringing work at the field to a halt.
Bashneft subsequently fired Alexander Dashevsky, senior vice president for oil and gas production, and Rinat Nagayev, head of its oil and gas department, over the spill.
Photos taken by satellite monitoring company ScanEx showed about 40,000 square meters were affected by the spill, but environmental groups said a lack of independent monitoring in the remote region made it impossible to verify the extent of the damage.
The Federal Service for Environmental, Technological and Atomic Inspection, which carried out an investigation into the incident, blamed the spill on faulty lifting equipment and the lack of a blow-out preventer.
It also cited a lack of experience in deep-well repair in Arctic conditions as a contributing factor.
Environmentalists estimate about 5 million tons, or 1 percent of annual production, is spilled in Russia annually, mostly from leaky pipelines.
Alexei Knizhnikov, director of WWF Russia's oil and gas program, said a lack of reliable data made it impossible to be certain about the size of the oil spill problem, but called the Trebs spill "average-sized."