Regulations will appear. There are already regulations about radiation exposure that will be immediately extended into space travel if no regulatory body acts quickly enough.
A short search gave me this number, apparently for the US:
> 20 mSv a year, averaged over defined periods of 5 years with no single year >50 mSv
Surely in such unusual circumstances any limits must be set as part of a cost benefit analysis from the point of view of the person concerned. One person might be rationally willing to risk higher exposure in the pursuit of knowledge.
A short search gave me this number, apparently for the US:
> 20 mSv a year, averaged over defined periods of 5 years with no single year >50 mSv
This basically prohibits paid-for space labor.