The first sugarcane plantations were introduced in the Dominican Republic by the Spanish colonizers in the beginning of the 16th century. Currently, agriculture is one of the most important sectors of the national economy, as sugarcane is the principal agricultural product of the country. The industry is concentrated in three businesses that control 75% of the sugarcane plantations: the State Sugar Board (CEA), which controls 50% of production, Casa Vicini, a national company, and Central Romana, a foreign company. The majority of production is found in the Southeast of the country. Over the course of many years, there were disputes between Haiti and Dominican Republic over borders that were defined through a treaty signed in January 1929. As a result, thousands of Haitians remained in Dominican territory, the majority of whom served as a labor force in the sugarcane fields. Accidents in the sugarcane fields are frequent and leave many workers mutilated. When they stop working, sugarcane workers have no right to retirement or benefits. Wages are extremely low and based on the quantity of cane that is cut, not on hours worked. Workers have no control over the weight of their production, and many times have no idea how much they will receive in compensation per ton of sugarcane they cut.