Assessing health, safety and security for the event is a very essential task. there are different ways of archiving this. the most common one is by doing a risk assessment, as this help to aliminate hazards that could potentially lead to injuries.
first aid cover- you are required by law to provide first aid cover at any event open to public.
The basic requipement for any event would be that the equipment and facilities are adequate and appropate for the circumstances and the first sid is readily available for anyone that is injured.