March 2
March 2, 1807 - The U.S. Congress abolished the African slave trade. It passed an act to "prohibit the importation of slaves into any port or place within the jurisdiction of the United States... from any foreign kingdom, place, or country."
Postal workers granted 8 hour day - 1913
U.S. Steel yields, recognizes the Steel Workers Organizing Committee as the sole representative for its workforce. The agreement led directly to many other steel firms recognizing the union - 1937
And this:

March 2, 1937 - John L. Lewis, president of the Congress of Industrial Organizations, and U.S. Steel President Myron Taylor signed a landmark agreement in which the company recognized the Steel Workers Organizing Committee as the sole representative for its workforce. The contract also included a 40-hour work week and pay for overtime. The agreement with U.S. Steel led directly to many other steel firms recognizing SWOC, even though the so-called Little Steel firms, large competitors of U.S. Steel, continued to resist unionization until after World War II began.
More than 6,000 drivers strike Greyhound Lines, most lose jobs to strikebreakers after company declares “impasse” in negotiations - 1990
Labor history found here:
http://www.unionist.com/today-in-labor-history & here:
http://www.workdayminnesota.org/index.php?history_9_03_02_2011