Bloomberg reports that Exxon Mobil Corp., the world’s largest publicly traded oil company, plans to halt its Sriracha refinery in Thailand as it modifies units to reduce sulfur in fuels, according to two people with knowledge of the work. The shutdown will start in September and last about five weeks. The shutdown will enable work to be completed and enable Exxon to produce low-sulfur fuels before Thailand’s switch to Euro-4 standards next year, which will limit allowable sulfur content in gasoline and diesel to 50 parts per million or less. Exxon said on July 29 that it began work on a clean-fuels project at the plant, with commissioning expected by the end of 2011. The company said on July 16 it would modify existing hydrotreating units to cut sulfur levels in gasoline and diesel to 50 parts per million and build a facility to reduce benzene in gasoline to 1 percent to meet stricter fuel specifications that will take effect on Jan. 1, 2012. The project, which the company estimates will cost $394 million, is progressing as planned.