The slick now covers an area of more than 2,000 square km, said John Amos, an oil spill specialist who reviewed satellite imagery obtained by Reuters. MARINE NATURE RESERVE THREATENEDThe Caroline Bezengi tanker, carrying an estimated 800,000 barrels of Russian oil and under international sanctions, ran aground on June 30. Ukraine has carried out assaults on a so-called shadow fleet carrying Russian oil, which the Caroline Bezengi is part of. Amos said this would rival the 1989 Exxon Valdez oil spill in sheer size. Environmental agencies and oil spill specialists estimated its size as far larger, noting the spread has accelerated dramatically since the beginning of August.