Biotech companies have extremely elaborate systems for approvals of human and animal subject trials. Pretty much every study has to go through an institutional review board, and these boards often have a bioethicist on hand do deal with tricky issues involving human experimentation.
One thing that you have to be really, really careful about if you get into this line of work is that you don't end up being the "corporate apologist." It's very easy for a corporation to say effectively "we don't have to worry about ethics since we have an expert worry about that for us." If you work for people that don't themselves have a well developed sense of right and wrong, you may end up in a situation where your job ends up coming up with elaborate excuses for why something that any average person would think is morally and ethically repugnant is perfectly fine. Alternatively, you could be in a situation in which you spend a huge amount of time looking at a small relatively minor issue, and avoid thinking about a bigger question which is really too uncomfortable to think about.