Answer:
Their control over a seasonal schedule.
Step-by-step explanation:
Early industries forced immigrants and African Americans who really wanted jobs and gave them jobs in mainly factories and railroad building. The factories, some of which were filled with smoke, polluting their lungs, or, having horrible chemicals in meat products(aka meatpacking) giving them diseases. This was ended by the meat inspection act, but they faced it. Now, for the long hours and awful pay. There were at least 4 riots I know of that rioted for better pay like the Haymarket riot. There was also a big group of American labour's that created the group known as Knights of Labour.
I can go much more in depth if need. ;)