What it is
Cast iron is iron with 2–4% carbon poured into a mould; carbon steel is the same chemistry with less carbon, rolled thin and light (woks, French frypans). Both are bare metal protected by “seasoning”. Enamelled cast iron fuses a layer of vitreous glass over the metal, so food never touches iron at all.
Why it’s safer
No synthetic coating to flake, no polymer to shed, and a service life measured in generations — a buy-once pan is itself a plastic-reduction strategy. High-heat searing, the job that destroys non-stick, is exactly what bare iron is for.
The honest caveats
Iron transfers into food — usually a feature. The classic quantification: acidic, moist, long-cooked foods (tomato sauce, applesauce) picked up several-fold more iron from iron cookware (J. American Dietetic Association, 1986) lab, with transfer declining as seasoning builds (J. Food Science, 1991). For most people — and anyone iron-deficient — that’s neutral to mildly helpful. The exception matters in Australia: hereditary haemochromatosis is common in people of northern-European descent, and anyone managing iron overload should cook acidic food in enamelled or stainless instead.
Seasoning is polymerised oil — yes, “polymer.” The honest answer: seasoning is fat oxidised and cross-linked into a hard, bonded coating, which is a polymer in the chemical sense. It’s food-derived, tightly adherent, and I found no study flagging it as a microplastic or toxicity source — the genuine cautions are the smoke during seasoning (ventilate; acrolein is unpleasant) and rancid surface oil on neglected pans. Black specks in food are carbonised food, not a documented hazard. Filed under: chemistry words are not automatically scary words.
Enamel is glass — with a vintage asterisk. Modern enamel from major makers meets the same lead-leach limits as ceramic glazes agency. Vintage and cheap no-name enamelware is the risk pocket — consumer XRF testing has repeatedly flagged lead in old enamel pots early (advocacy-grade evidence, not peer-reviewed, and I label it as such). A chip on the cooking surface exposes harmless iron but leaves sharp glass edges — retire chipped-inside pieces.
What I do
The titanium pan and induction cooktop arrived first, but cast iron is pencilled in for the searing jobs, and an enamelled pot for the slow tomato work that neither bare iron nor new stainless loves. Vintage enamel stays at the op-shop.