The Jan. 3, 1908 NYT reports an interesting negative exteranality arising from a work stoppage of the Bakers' Union in Chicago:

Four men, said to be members of the Bakers' Union, have been arrested on the charge of putting acid on hundreds of loaves of bread distributed among the Jewish residents on the west side. A strike is in progress at a local bakery, and it is alleged that strike sympathizers threw acid as wel as iodoform on wagon loads of bread and rolls after they had left the bakery.