There was a time when America was noted for record breaking achievements like this, Chicago towards the end of the 19th century springs to mind.
They weren't too bothered back then about worker safety and the like, much like China today
The video claims there were no injuries in this project, though there's no way to tell how veracious that claim is.
I guess that's a little like saying: i jumped off a cliff into the sea and didn't get hurt, countless people do and don't get hurt. At the same time though, there's a great risk of me hitting something on the way down if it's very windy or me drowning because I landed awkwardly in the water(I've experinced this one jumping from about 10ft as a child).