How dangerous was the original "Chicago Pile" atomic reactor, built in 1942?

I was wondering how dangerous the first atomic reactor was, bearing in mind that it was built and operated in the middle of Chicago, with no previous experience of atomic reactors, at all. https://en.wikipedia.org/wiki/Chicago_Pile-1 The design was simple enough -- tons of Graphite piled on top of tons of Uranium. And the output was just one-half Watt. In more general terms, if the danger was relatively minimal, does this suggest the possibility that research on nuclear reactors might be pursued with less stringent regulation than currently applies, at least in cases in which the design is simple enough, and the power outlet is small enough?