Ceramic pans are marketed as "safe," but their coating degrades within 12-18 months, exposing the metal base underneath—which often contains lead, cadmium, or aluminum that leaches into acidic foods.
Cast iron requires constant seasoning with oils that oxidize and turn rancid, plus it leaches excessive iron into food (problematic for people with hemochromatosis).
Stainless steel contains nickel and chromium that migrate into food when cooking acidic ingredients like tomatoes or lemon.
Pure titanium is the only material that's completely chemically inert—it won't react with food, release particles, or degrade over time.