It is very important to realize that Texaco's history of supporting fascist powers in the Spanish Civil War, which extended into WWII, is only one illustration of a number of such corporations that supported fascism. (IT&T, General Motors, Ford are among many others that I immediately recall.) It is very important to obtain a meaningful understanding of this devastating war to see it as a dress rehearsal for WWII. This history has been subject to gross distortions by capitalist historians in an effort to portray it as a kind of folklore for their subjects--ordinary workers and their families--as a contest between us "good guys", the "democratic" powers, against the fascist "bad guys".
The history is much too complicated to review for this blog. Thus I recommend that you read Homage to Catalonia by George Orwell and The Spanish Civil War by Paul Preston among others. The important factors in the war were the following: the Soviet revolution of 1917, the anarcho-communists that dominated the defense of the Spanish Republic, and the natural fascist proclivities (see this, this, and this) of the capitalist ruling classes of Western countries.