Throughout US history, union strikes were implemented to improve unfair and unsafe working conditions, resolve labor and wage disparities, and secure workplace protections for the worker. Here are a few famous strikes that effectively changed the workplace.
Sources:
https://aflcio.org/about-us/history
https://www.investopedia.com/the-10-biggest-strikes-in-u-s-history-4773384#citation-11
https://www.vox.com/the-highlight/2019/6/28/18662706/chicago-teachers-unions-strike-labor-movement