My general impression is that worker safety was pretty much disregarded compared to modern standards.
A quick search turned up this piece[1] on 16 deaths around 1904 during construction of a NYC subway line. There are famous pictures such as this one of construction of high rises in New York[2] without any safety equipment whatsoever. But it was built in 14 months! All that safety gear is expensive and slows down construction. In climbing, we often joke 'no belay, no delay', because of how fast you can climb when you don't take the time to fix your ropes, etc. [3]