In a medium bowl, beat egg. Add sugar, oil, and milk; mix well and set aside.In large bowl, sift together flour, baking powder, and salt. Make a well in the center of the flour mixture and add the egg mixture, stirring just to moisten. Fold in blueberries. Spoon into a greased muffin tins and let stand for 10 minutes.Bake in a 400°F (205°C) oven for 25 to 30 minutes, or until done. Cool on wire rack.