Are these sentences correct:
1) For safety reasons, the stairs must not be used by members of the public.
2) The stairs must not be used by members of the public for safety reasons.
The first one is better than the second one, but is the second one incorrect?
The first is better. It puts the emphasis on safety being the reason for what follows. If I were to use the second construction I would probably put "for safety reasons" in brackets to distance it from "members of the public".
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.