Director General of the Pollution Control Department Atthapol Charoenchansa said the leak at the pipeline owned by Star Petroleum Refining Public Company Limited started late on January 25, southeast of the Map Ta Phut industrial estate, a major petrochemical complex.
He earlier said Koh Samet, a resort island off Rayong province popular among foreign tourists, could be impacted by January 28, but has since revised the threat level.
Sophon Thongdee, Director General of the Department of Marine and Coastal Resource, said the cleanup should conclude on January 27 and there was no major damage to marine life or habitat.
However, experts would be dispatched to carry out further assessment, he said.
In a statement, the company said the leakage has not impacted refinery operation.
