Can you use metal utensils on cast iron without releasing anything harmful?
Mostly yes. Metal can scrape seasoning, but cast iron has no PTFE coating. Avoid long acidic cooking in cast iron.
What's actually in it
Cast iron is iron with a thin layer of baked-on oil called seasoning. A metal spatula can scratch that seasoning. That is a pan-care issue first, not the same as scraping a nonstick coating.
Cast iron has no PTFE coating. If seasoning flakes, clean the pan and reseason it. Do not cook with loose flakes or rust in the pan.
What the research says
A 2025 Journal of Hazardous Materials lab study found PTFE micro and nanoplastics can enter intestinal cells and cause oxidative stress, mitochondrial damage, and DNA damage. That source is about PTFE particles, not cast iron.
A 2025 International Journal of Environmental Health Research study boiled acidic, alkaline, and drinking-water solutions in cookware. It found metal release changed by pH and pan material, and cast iron released metals under acidic and alkaline test conditions.
For normal cast iron cooking, metal utensils are okay if the pan is well seasoned. Use wood or stainless steel gently. Do not simmer tomato sauce, vinegar, or lemon-heavy food in cast iron for a long time. If the pan is rusty, deeply pitted, or shedding black flakes, scrub and reseason before cooking.
The research at a glance
| Study | Journal | Year |
|---|---|---|
| Polytetrafluoroethylene (PTFE, Teflon) microplastics and nanoplastics induce oxidative stress, mitochondrial damage, and genotoxicity in human intestinal cells. | J Hazard Mater | 2025 |
| Heavy metal transitions from cooking utensils to different solutions. | Int J Environ Health Res | 2025 |