Cast Iron Skillet vs. Hard-Anodized Aluminum Pan

Hard-anodized aluminum undergoes an electrochemical process that thickens and hardens the natural aluminum oxide layer, making it more resistant to corrosion and leaching than standard aluminum. The anodized surface is non-reactive under normal cooking conditions. However, most hard-anodized cookware is also coated with PTFE on the cooking surface to provide non-stick properties — if so, the coating concerns of Teflon apply.

Cast iron is completely coating-free and does not involve any synthetic surface treatment. It rates as 'best' precisely because its composition is so simple: iron, carbon, and polymerized oil seasoning. Cast iron leaches trace dietary iron, which is nutritionally neutral or beneficial for most people.

Hard-anodized rates 'caution' primarily because the anodization process alone rarely appears in consumer cookware — almost all hard-anodized pans include a PTFE coating on top. If you find a hard-anodized pan without any non-stick coating, its safety profile is closer to stainless steel. But with the PTFE coating that most include, the fluoropolymer risks apply. Cast iron is the clearly safer choice: no aluminum, no synthetic coating, no ambiguity about what the cooking surface is made of.