Can you use metal utensils on cast iron without releasing anything harmful?
Yes. Cast iron isn't coated, so a metal spatula won't scrape off plastic. It just adds more iron.
What's actually in it
Cast iron is solid iron with a polymerized-oil seasoning. A metal spatula can scratch the seasoning, but the underlying material is still just iron. A new layer of seasoning rebuilds with oil and heat. No PFAS coating, no plastic, nothing to lose.
Compare to nonstick: a single scrape of a metal utensil can release PTFE flakes into food.
What the research says
A 2025 study in J Hazard Mater quantified the damage PTFE micro and nanoparticles do to gut cells: oxidative stress, mitochondrial damage, and DNA breaks. A 2025 study found cast iron leaches iron, not problematic metals.
Use any spatula on cast iron: metal, silicone, or wood. Reseason after deep scrapes by rubbing in a thin film of oil and baking upside down at 230°C for an hour.
The research at a glance
| Study | Journal | Year |
|---|---|---|
| PTFE microplastics induce oxidative stress in human intestinal cells. | J Hazard Mater | 2025 |
| Heavy metal transitions from cooking utensils. | Int J Environ Health Res | 2025 |
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