Today in Labor History July 7, 1931: Construction began on the Hoover dam. 16 workers and camp residents died from heat exhaustion during a single month of construction. Temperatures routinely soared over 110 degrees Fahrenheit. Several strikes led to nominal improvements in working conditions. Thousands of men were employed in the highly segregated project. Only 30 African Americans were allowed to work at any given time and Chinese workers were officially excluded. The Wobblies (IWW) tried to organize the men and sent in 11 organizers who were promptly arrested. Eugene Nelson, a Wobbly hobo, writes about it in his wonderful biographical novel, “Break Their Haughty Power.”