Seyed Hassan Mirsoltani told Shana that Shahid Tondgouyan oil refinery\'s upgrading plan covers fourteen units of which 10 units have been delivered for initial startup and the four remaining units will also come online up to the end of the first half of the current Iranian calendar year in mid September. Stating that all managerial elements of the plan including contractors and consultants are Iranian, the official noted that more than 70 percent of the equipment and needed materials of the plan including catalysts, control systems and all the units\' pumps have been built by domestic companies. \"More than 6,500 billion rials (USD500mln) have been invested in the project of which 60 percent have been provided by the National Iranian Oil Refining and Distribution Company, 8 percent through selling participation bonds (approximately 500 billion rials) and 32 percent (nearly 2.000 billion rials) via Bank Mellat\'s Energy Fund,\" the official said. Upgrading plan of Shahid Tondgouyan oil refinery aims to improve the quality of the refinery\'s oil products by desulphurization from kerosene and gasoil in order to produce gasoil and kerosene compatible with euro-4 standards which are going to come on stream soon. The project is an environmental plan which is being implemented by the National Iranian Oil Engineering and Construction Company (NIOEC) and upon completion will produce almost 110 million tons of sulfur per day as well.