Volcano cake what kind of sparklers do i need? some one told me that sparklers would poison food?

My son had this at the rainforest cafe and i plan to make it for his birth day. I have access to both kinds of sparklers the wooden stick kind and the metal. At the cafe they used the metal kind are thay made for the cafe or am i right in thinking they are the same that anyone can buy. It is such an impressive affect I hope that I am right so i can make it for him and his friends