THe best advice I can give you is to be yourself. Think about the questions they may ask you, e.g:

• Why do you want to get into Health & Safety?
• What skills do you posses which you think you can bring to the role?

Further to this make sure you have a couple of questions in your back pocket. Most feel that when the interviewer has finsihed asking questions the interview is over, not so, so if you can ask a couple of pertinent questions at the end this will help you too.

There is a lot of advice and tips on this, but at-the-end-of-the-day all you can do is your best, so make sure you prepare.