Freezer to smoker

Hello. I have a True, model T-23 stainless freezer and would like to transform it into a smoker using an internal propane burner. Would it be safe to leave the CFC free polyurethane foam inside the walls? Or shoud it be removed and replaced with other insulation? Also, the inner walls are baked on, painted aluminum, does the paint need to be removed? I do not want any contaminants or toxic fumes created when smoking. Any advice would be helpful. Thanks, chasser