The operator of Kazakhstan's offshore Kashagan oil field in the Caspian Sea on April 2 denied reports of an oil spill and said its facilities were working normally.
Globus, an environmental organization in the Central Asian country, said earlier that satellite imagery had captured a large oil spill in the northern Caspian Sea near Kashagan.
Globus director Galina Chernova said on Facebook on March 30 that a slick of around 7 square kilometers had formed and drifted to the northern part of the sea, citing images from a European satellite.
An accidental oil leakage during production, discharge of industrial water containing petroleum products, or a possible emergency situation with service vessels are among the potential causes of a leak.
But the North Caspian Operating Company (NCOC), a consortium largely owned by the Western oil companies that operate the offshore field, said the satellite images showed a different, natural phenomenon, and subsequent images of the same location showed nothing unusual.
The company said it had studied the area and found no irregularities.
The NCOC on March 29 held public hearings on its work in the marine complex. Company managers said then that the company did not allow pollution of the air or the sea and referred to reports and presentations of NCOC specialists and project developers in which they said the company was striving for zero emissions in the local environment.
Environmentalists, however, remained dubious and have asked the NCOC what happened, who is responsible, and how the spill would be cleaned up.
Questions were also addressed to the Ecology Department of the Atyrau region about what measures had been taken to deal with the alleged spill and whether damage to the marine environment and biodiversity had been determined.
NCOC did not comment on the environmentalists' questions.
Kashagan, one of Kazakhstan's largest oil fields, is being developed by the NCOC, which includes Shell, Eni, TotalEnergies, and Exxon Mobil.
The Ecology Department of the Atyrau region, which borders the Caspian, has said it would inspect the area and take samples at the oil production site.
"If these facts are confirmed, the Department of Ecology for the Atyrau region will conduct an unscheduled inspection of the NCOC company. The results will be reported," the department said in a statement.