 The growing company assumed the reverted assets of the Tropical Oil Co. that began oil activities in 1921 in Colombia with the implementation of the Cira-Infantas Field in the Middle Magdalena River Valley.Ecopetrol undertook activities in the oil chain as a state-owned industrial and commercial company in charge of administrating the nation's hydrocarbon resources, and grew as other concessions reverted and became part of its operation.The nationalization of Ecopetrol was not smooth and met with some opposition and skepticism as to how the company could in fact be able to keep up with the complex and expensive operations without outside expertise in the changing international market.