Final answer:
The serious problem that Carnegie's workers had to contend with at this time was health hazards. Workers faced injuries, loss of fingers and hands, breathing problems, heat exhaustion, and exposure to toxic chemicals. The conditions in the factories and mines were unsafe, resulting in frequent accidents and health issues for the workers.
Step-by-step explanation:
The serious problem that Carnegie's workers had to contend with at this time was Health hazards.
The long hours and mechanized labor in Carnegie's factories took a toll on the workers' health and safety. Workers faced various health hazards such as injuries, loss of fingers and hands due to machine parts, back problems, miscarriages, breathing problems, hearing loss, heat exhaustion, and exposure to toxic chemicals. They also endured dangerous conditions in mines.
The conditions in the factories and mines were unsafe, resulting in frequent accidents and health issues for the workers.