How safe is cast iron?

Quick Overview

Cooking with seasoned cast iron or carbon steel pans does not present a scientifically proven health risk from consuming polymer flakes, despite common concerns raised in online comments; the polymerization process that creates the seasoning layer occurs at temperatures far below the oil's smoke point, and any resulting flakes are negligible in quantity and not linked to documented health issues like cancer or cardiovascular disease.

Key Points: Polymerization, which creates the seasoning layer on cast iron/carbon steel, occurs when oil is heated above approximately 250°F (120°C), well below the smoke point of most cooking oils (>350°F or 180°C). While small flakes of seasoning may sometimes lift off, scientific evidence does not support claims that ingesting these flakes poses health risks like cardiovascular disease or cancer. The fumes generated during the seasoning process itself (heating oil until it smokes) are a greater concern for indoor air quality, as cooking in general produces emissions that can exceed health standards in poorly ventilated homes. Experts contacted for the video indicated that there is no scientific basis to prove that the seasoning layer or the seasoning process itself is inherently unsafe for cooking. Regularly seasoning pans does not require heating the oil to its smoke point; wiping out excess oil after heating is sufficient to build the seasoning layer. The video contrasts the lack of evidence for seasoning harm with documented health risks associated with inhaling fumes from cooking or from substances like talc powder.

Context: This video addresses widespread public concern and online commentary regarding the safety of cooking with seasoned cast iron and carbon steel pans, specifically focusing on whether ingesting flakes of the polymerized seasoning layer poses health risks such as cancer or cardiovascular disease. The host investigates the scientific basis for these fears by examining the chemistry of oil polymerization and referencing expert opinions.