Bob, the key to preventing a recurrence is understanding exactly what caused your accident. It may have been a blade or fence misalignment as has been suggested. If you find that is not the case, however, there are other questions:
You didn't say which part was against the fence, the 16" workpiece or the 2" offcut. You didn't say which piece was kicked back. You didn't say whether you were pushing/guiding with both hands or one hand only.
When you say you were "crosscutting" a piece of plywood, that leads me to suspect you may have had the 16" workpiece on the left side of the blade and the 2" offcut against the fence. If you were pushing with your left hand, the workpiece may have skewed on the table as it separated from the offcut, moving it into the back teeth of the blade.