The third 1 million tonnes per year distillation unit was commissioned in September 1967 to process Ankleshwar and North Gujarat crudes. In December 1968, Udex plant was commissioned for production of benzene and toluene using feedstock from CRU. By 1974-75 with in-house modifications, the capacity of the refinery increased by 40% to a level of 4.2 million tonnes per year. To process imported crude the refinery was expanded during 1978-79 by adding another 3 million tonnes per year crude distillation unit along with downstream processing units including vacuum distillation, visbreaker and bitumen blowing units. By 1980-81 this unit started processing Bombay High crude in addition to imported crudes. It was the first time that Indian engineers independently handled a project of that scale.