Thai authorities have sued a chemical company for the oil spill it caused in the Thai Gulf, which led to an estimated loss of more than 100 million U.S. dollars. Thailand\'s Marine Department on Tuesday filed a complaint with the local police in eastern Rayong province against the PTT Global Chemical Plc (PTTGC), a subsidiary of PTT Plc, Thailand\'s state- owned oil and gas conglomerate, for the oil spill from its offshore pipeline in Royong. The move was aimed at requesting the company to take responsibilities in cleaning up the oil spill and paying compensations. Marine Director-General Sornsak Saensombat said the complaint is part of a normal legal procedure, adding that the department has set up an office to receive complaints and reports of losses from local people. He said the severity of the leak was at the intermediate level which requires state intervention in the clean-up operation. The spill took place early Saturday about 20 kilometer southeast of the Map Ta Phut seaport in Rayong, and about 35 kilometer from the popular holiday island of Samet, also in Rayong. Crude oil from an offshore Omani tanker was being transferred to a pipeline, operated by PTTGC, for a refinery when a leakage was detected. About 50 tonnes, or 50,000 liters of oil was poured into the sea. More than 500 staff from PTTGC and Thai Navy have been working continuously for more than 48 hours to clean the oil slick on the picturesque sand beach of Phrao Bay of Samet island. Sornsak said on Wednesday that only 20 to 25 percent of the slick is still on the beach, adding that the clean up of oil spill on Phrao bay should be complete on Wednesday, while the clean up of sand and rocks could be finished in a week. Chemicals will not be used for the clean-up near beaches, he said, adding that the collected oil residues from the slick will be later shifted to a processing facility for treatment, he said. Somsak said the PTTGC must submit a rehabilitation plan within August and all parties concerned would be invited to discuss the measures to restore affected areas of the environment. He attributed the slow process in tackling the problem in the first few days to delays in delivering clean-up equipment to the site, adding that strong wind was another factor that hampered the cleanup mission. Prime Minister Yingluck Shinawatra, who is on an overseas trip, said she was concerned about the incident and has ordered a systematic response to cope with the oil leak. Minister of Energy Pongsak Ruktapongpisa said all parties affected by the leak would be compensated. Meanwhile, Chairat Trirattanajarasporn, head of Rayong Tourism Association, said the local tourism industry had lost about one- fifth of its annual revenue or about 102 million dollars so far, while a group of fishermen said they were losing 172,000 dollars in daily revenue.