1. Rinse beans with running cold water and discard any stones or shriveled beans. In 5-quart Dutch oven over high heat, heat beans and 6 cups water to boiling; cook 3 minutes. Remove Dutch oven from heat; cover and let stand 1 hour. Drain and rinse-beans.
2. Return beans to Dutch oven. Add 3 cups water; over high heat, heat to boiling. Reduce heat to low; cover Dutch oven and simmer 40 minutes, stirring occasionally.
3. Meanwhile, in 10-inch skillet over medium heat, cook salt pork until well browned, about 10 minutes. Add onion and green pepper; cook until tender, stirring occasionally. Stir onion mixture, tomato sauce, salt, oregano, garlic powder, and pepper into beans; cook 40 to 50 minutes, until beans are tender and mixture thickens.