Excerpts from the report Introduction: Sugar is the principal commodity exported from Puerto Rico. More than a million tons, representing 90 to 95 percent of the total production of the island, are shipped to continental United States each year. The mainland United States receives about one-eighth of its sugar requirements from Puerto Rico. Approximately 90 percent of the total shipments to mainland ports from this source is in the form of raw sugar. This raw sugar is sold to mainland refiners on the basis of the weight and polarization of the sugar when delivered. During the past few years producers have been concerned about decreases in weight and polarization of raw sugar between the time it is produced and its arrival at mainland ports. The general belief throughout much of the Puerto Rican sugar industry is that losses of weight in raw sugar shipped to the United States, especially to northern ports, are excessive and that there is no gain in polarization on most shipments to offset the weight loss. The Puerto Rican sugar industry, therefore, requested that a study be made of the losses of raw sugar in storage and shipment.