HPCL was incorporated in 1974 after the takeover and merger of erstwhile Esso Standard and Lube India Limited by the Esso (Acquisition of Undertakings in India) Act 1974. Caltex Oil Refining (India) Ltd. (CORIL) was taken over by the Government of India in 1976 and merged with HPCL in 1978 by the CORIL-HPCL Amalgamation Order, 1978.