Firstly your example is wrong because that's a government project. If government cared their would be less deaths in their projects and they would be the shinny example of health and safety, which they're not.
Secondly people should be grown up enough to take responsibility for themselves and not do reckless stuff that would get them killed, you don't need government regulations for that.
Thirdly an accident is an accident learn from it and move on. I'm all for education telling people not to be stupid with heavy machinery, but no government intervention is necessary for that.
Any argument for regulations to nanny and protect people against themselves rest solely on the idea the people are too stupid to function without central control telling them what is acceptable. Then you have to make a case that that centralised authority actually know better than the average person about what is best for them, which eventually leads to communism if you take it all the way, basically the opposite of free market and private property. The government knows best and everyone works for the greater good. That line of reasoning has proven to be murderous in the past. It is also nonsense that you can only implement the good part of that and not take it all the way. The bureaucracy will eventually grow out of control and corrupt like we see here by us.
The only argument you can make for the need of government and agents the free market is one of funding for big projects, because the government can tax it's populace which a private enterprise cant do. But even that falls flat as there are ways around that and governments has proven themselves inefficient.