Preheat oven to 350°. Mash bananas with a fork in a large bowl. Stir in sugar and next 5 ingredients. Let stand 5 minutes or until oats soften.
Combine flour, baking powder, and baking soda in a small bowl. Add to banana mixture alternately with oil, stirring just to incorporate. Fold in blueberries. Pour into a greased 9- x 5-inch loafpan, and bake 50 minutes or until a wooden pick inserted in center comes out clean.