The SS Las Choapas was an oil tanker built in 1898. She was originally commissioned by Standard Oil of New Jersey and built by the Delaware River Iron Ship Building and Engine Works of Chester, PA. As the SS Atlas she saw service in World War I before being sold in the 1920s to the Italian company Ditta G.M. Barbagelata, of Genoa. She was seized while docked at Tampico, in Mexico on 8 December 1941 by the Mexican government and renamed, to be operated by Petróleos Mexicanos (Pemex), and homeported in Tampico.