HexClad is a hybrid pan with a laser-etched stainless steel surface over an aluminum core, with PTFE filling the recessed valleys of the hexagonal pattern. This means every HexClad pan contains PTFE — the same polymer used in Teflon. HexClad's PTFE is claimed to be PFAS-free, but it is still a fluoropolymer that can release fumes if overheated above 500°F and degrades over time.
Cast iron has no synthetic coating whatsoever. It is simply iron and carbon, seasoned with polymerized oil. There is nothing to off-gas, no coating to degrade, and no fluoropolymers involved. The safety profile is fundamentally simpler and more transparent.
For anyone concerned about PFAS or fluoropolymer coatings, cast iron is the clear winner. HexClad is rated 'caution' because its PTFE component, however small, introduces coating-related risks that cast iron completely avoids. HexClad's main appeal is convenience — the stainless ridges create a non-stick-like surface without full coating dependence — but that engineering compromise means it cannot match cast iron's uncoated safety profile. If toxin avoidance is your priority, cast iron wins decisively.