A little bit of carbon (2-4%) and silicon. Otherwise it's just iron. It should also be noted that with a properly seasoned cast iron pan, the food isn't intera

A little bit of carbon (2-4%) and silicon. Otherwise it's just iron. It should also be noted that with a properly seasoned cast iron pan, the food isn't interacting as much directly with the iron, since the seasoning layer (polymerized fats) is in the way.