Fear that thawing permafrost caused damage to storage tank.
Company’s bulldozer was in such rush to dismantle pipes after being filmed by ecologists that it crashed a police car.
Russian ecologist says his undercover trip shows Arctic ecosystem is irreversibly damaged, as whistleblower in ecological watchdog quits and leaves town.
Toxic fuel from 21,000 ton leak reaches pristine lake, bypassing floating booms, as rivers of diesel pollution cover-up is exposed.