May 02 
Chicago's first Trades Assembly, formed three years earlier, sponsors a general strike by thousands of workers to enforce the state's new 8-hour-day law. The one-week strike was unsuccessful - 1867
 
Birth of Richard Trevellick, a ship carpenter, founder of American National Labor Union and later head of the National Labor Congress, America’s first national labor organization - 1830
 
First Workers’ Compensation law in U.S. enacted, in Wisconsin - 1911
 
President Herbert Hoover declares that the stock market crash six months earlier was just a "temporary setback" and the economy would soon bounce back. In fact, the Great Depression was to continue and worsen for several more years - 1930
 
German police units occupied all trade unions headquarters in the country, arresting union officials and leaders. Their treasuries were confiscated and the unions abolished. Hitler announced that the German Labour Front, headed by his appointee, would replace all unions and look after the working class - 1933

A fire at the Sunshine silver mine in Kellogg, Idaho, caused the death of 91 workers who died from carbon monoxide poisoning, likely caused by toxic fumes emitted by burning polyurethane foam, used as a fire retardant - 1972

May 03
Four striking workers are killed, at least 200 wounded, when police attack a demonstration on Chicago’s south side at the McCormick Harvesting Machine plant. The Haymarket Massacre is to take place the following day - 1886
(Attacks against strikers and the very existence of organized labor persist to this day.  From Blackjacks to Briefcases is the first book to document the systematic and extensive use by American corporations of professional unionbusters, an ugly profession that surfaced after the Civil War and has grown bolder and more sophisticated with the passage of time.)
 
Eugene V. Debs and other leaders of the American Railway Union are jailed for six months for contempt of court in connection with Pullman railroad car strike - 1895
 
Pete Seeger, folksinger and union activist, born in Patterson, N.Y. Among his songs: “If I Had A Hammer” and “Turn, Turn, Turn” - 1919
 
May 04
Haymarket massacre. A bomb is thrown as Chicago police start to break up a rally for strikers at the McCormick Harvesting Machine Co. A riot erupts, 11 police and strikers die, mostly from gunfire, and scores more are injured - 1886
 
May 05
National Typographical Union founded, Cincinnati, Ohio. It was renamed the Int’l Typographical Union in 1869, in acknowledgment of Canadian members. When the ITU merged into CWA in 1986 it was the oldest existing union in the U.S. - 1852
 
On Chicago’s West Side, police attack Jewish workers as they try to march into the Loop to protest slum conditions - 1886
 
Some 14,000 building trades workers and laborers, demanding an 8-hour work day, gather at the Milwaukee Iron Co. rolling mill in Bay View, Wisc. When they approach the mill they are fired on by 250 National Guardsmen under orders from the governor to shoot to kill. Seven die, including a 13-year-old boy - 1886
(Unions for Beginners: It is a time when unions have returned to the front pages of newspapers and blogs and demonstrators are in the streets of America every day. It is a time when the right wing has tried to strike the final blow against what remains of the right to collective bargaining. It is a time when millions of members of the middle class are falling through the cracks in a downward economic trend that parallels the decline of unions. It is this time when people are turning again to the history of unions. Unions for Beginners provides an introduction to that essential history.)
 
Nineteen machinists working for the East Tennessee, Virginia, and Georgia Railroad gather in a locomotive pit to decide what to do about a wage cut. They vote to form a union, which later became the Int’l Association of Machinists - 1888
 
Italian-American anarchists Nicola Sacco and Bartolomeo Vanzetti are arrested in Boston for murder and payroll robbery. Eventually they are executed for a crime most believe they did not commit - 1920
 
Heavily armed deputies and other mine owner hirelings attack striking miners in Harlan County, Ky., starting the Battle of Harlan County - 1931
 
John J. Sweeney, president of the Service Employees Int’l Union from 1980 to 1995, then president of the AFL-CIO from 1995 to 2009, born in the Bronx, N.Y. - 1934
 
Lumber strike begins in Pacific Northwest, will involve 40,000 workers by the time victory is achieved after 13 weeks: union recognition, a 50¢-per-hour minimum wage and an 8-hour day - 1937
 
The U.S. unemployment rate drops to a 30-year low of 3.9 percent; the rate for Blacks and Hispanics is the lowest ever since the government started tracking such data - 2000
 
May 06
Works Progress Administration (WPA) established at a cost of $4.8 billion—more than $80 billion in 2015 dollars—to provide work opportunities for millions during the Great Depression - 1935
 
Four hundred Black women working as tobacco stemmers walk off the job in a spontaneous revolt against poor working conditions and a $3 weekly wage at the Vaughan Co. in Richmond, Va. - 1937
 
May 07
The Knights of St. Crispin union is formed at a secret meeting in Milwaukee. It grew to 50,000 members before being crushed by employers later that year - 1867
 
Two die, 20 are injured in “Bloody Tuesday” as strikebreakers attempt to run San Francisco streetcars during a strike by operators. The strike was declared lost in 1908 after many more deaths, including several in scab-operated streetcar accidents - 1907
 
Philadelphia’s longest transit strike ends after 44 days. A key issue in the fight was the hiring and use of part-timers - 1977
 
May 08
The constitution of the Brotherhood of the Footboard was ratified by engineers in Detroit, Mich. Later became the Brotherhood of Locomotive Engineers - 1863
 
About 200 construction workers in New York City attack a crowd of Vietnam war protesters four days after the Kent State killings. More than 70 people were injured, including four police officers. Peter Brennan, head of the New York building trades, was honored at the Nixon White House two weeks later, eventually named Secretary of Labor - 1970
 
Some 12,000 Steelworker-represented workers at Goodyear Tire & Rubber win an 18-day strike for improved wages and job security - 1997

—Compiled and edited by David Prosten