I would expect fewer safety issues, since learnings from previous years can be taken into account during design, which isn't easy to do in existing factories.
Both effects could be in place at the same time, in which case you would expect a higher rate of workplace accidents initially, and a lower rate in the mid- to long-term.
Until either of us finds studies on this topic it's meaningless speculation, because I honestly can't imagine more accidents, even initially, if things are done as they should be.