I. Introduction -- II. Summary and Conclusions-- III. Recommendations -- IV Survey Methods and Results -- Flow Measurement -- Sampling and Analysis. The Commonwealth Oil Refining Company, Inc. (CORCO) at Penuelas, Puerto Rico operates a Class C oil refinery-petrochemical facility consisting of a 100,000 barrel/day (bbl/d) crude oil refinery and 50,000 bbl/d crude naphtha petrochemical works. The refinery receives crude oil from South America and Middle East for production of gasoline, kerosene, jet fuel, diesel oil, fuel oil, propane, butane, LPG, and naphtha. The petrochemical works converts naphtha to aromatics, such as BTX (benzene-toluene-xylene), orthoxylene, and raffinate. These compounds are intermediates which are used to produce plasticizers, emulsions, latexes, lacquers, paints, polyester fibers, tire cords, nylon fibers, carpets, plastics, etc.