The Nagapattnam Refinery also known as Cauvery Basin Refinery[1] was the second oil refinery constructed by Chennai Petroleum Corporation Limited. It is situated at Cauvery Basin at Nagapattinam.[2] The initial unit was set up in Nagapattinam with a capacity of 0.5 million metric tonnes per annum in 1993 but later on in 2002 this was boosted to 1 megaton per annum. LPG is separated out in a gas treating unit built in 1996.[3]