July 21

Local militiamen are called out against striking railroad workers in Pittsburgh. The head of the Pennsylvania Railroad advises giving the strikers "a rifle diet for a few days and see how they like that kind of bread." - 1877
 
Compressed air explosion kills 20 workers constructing railroad tunnel under the Hudson River - 1880
 
IWW leads a strike at Hodgeman's Blueberry Farm in Grand Junction, Mich. - 1964
 
Radio station WCFL, owned and operated by the Chicago Federation of Labor, takes to the airwaves with two hours of music. The first and only labor-owned radio station in the country, WCFL was sold in 1979 - 1926
 
A die-cast operator in Jackson, Mich., is pinned by a hydraulic Unimate robot, dies five days later. Incident is the first documented case in the U.S. of a robot killing a human - 1984