Since most local coral reef is hump coral which grows very slowly at 1-4 centimetres a year, "We don't know how long it will take to recover from the impacts of this spill and how much damage has been caused there," he added.
The oil slick formed about 20 kilometres off the coast of the eastern province of Rayong, drifting for 35 kilometres towards Koh Samet Island, a tourist resort near Bangkok, famous for its white beaches.