Reply #5: Yes

[underpants]

but it was at least the second

Battle of Blair Mountain
http://en.wikipedia.org/wiki/Battle_of_Blair_Mountain
On orders from the famous General Billy Mitchell, Army bombers from Maryland were also used to disperse the miners, a rare example of Air Power being used by the federal government against US citizens. A combination of gas and explosive bombs left over from the fighting in World War I were dropped in several locations near the towns of Jeffery, Sharples and Blair. At least one did not explode and was recovered by the miners; it was used months later to great effect during treason and murder trials following the battle.