Unsafe and unsanitary work conditions in the early 1900s were a problem leading to the development of work-related sickness and fatalities.
In the early 1900s, working conditions were miserable, for instance they worked outside in all seasons, exposed to rain and snow, extreme heat and even cold. On top of that, workers often got sick or passed away due to the long hours and unsanitary conditions.
However, worker safety has widely improved since the early 1900s in the U.S.