Trumpy: to answer part of your question as to why there is no single nationwide safety standard in America. Thats easy.
There are pretty much no nationwide standards in America for anything. Drivers licenses on done on a state by state basis. Yes, it is true that each state will (general rule) accept another states drivers license as proof of competence the same is not true with other types of licenses.
I have a Texas Masters Electrician license, some states will accept it and let me work there, with a fee of course. Others will not accept it and I must take the local test, with a fee of course. Funny thing is they all use the same code book. Yes, I know some amend it slightly.
Where I work there is a PE ,which means he is an engineer who took a long test. He got his license in California. Moved to Texas and they would not accept it. I am not sure of the details but he meet some requirements that Texas has that California did not.
Lets not even get started on building permits. Two buildings across a street across city limits can have widely varying inspection requirements
Its just the way it is here.