Tobacco is very sensitive to 2,4-D which can drift considerable distances.  Damage, however, is usually isolated to 
those leaves that are in the development stage at the time of exposure.  Older leaves and new leaves will be normal.
Note the ruffled edges of the leaf on the left and the exaggerated leaf tip on the bud leaf on the right.

Pictures courtesy of Tom Fowler, Missouri Tobacco Specialist

Picture courtesy of Mike Pyles, Trimble Co.