To get young children involved in health and safety issues, I would probably do the normal 'rules and why we have them' talk.
Why we musn't jump from the climbing frame or similar
![Bawling](images/smilies/bawling.gif)
Why we use our quiet voices and walking feet
![Sigh](images/smilies/sigh.gif)
How to deal with strangers
![Highfive](images/smilies/highfive.gif)
When going on a trip, how should we arrange ourselves and why
![Spin](images/smilies/spin.gif)
Whay could happen if we played with matches :sorry:
You could make up a display covering some of these ideas with photos of the children in role play?