Yes, assuming you have US Business Account - there's some very good info here. The steps are explained there. As for is it safe to do so - assuming you have faith in your accountant - yes. Note, when you setup the person, you grant specific access rights in addition to assigning a User ID (which is not an email address) and a Password. The person cannot change either of these on their own and can only access features of your account that you give them permission for.