Carbon Steel vs. Non-Stick Cookware
2025-09-18
Over the last year or two I’ve been seeing a lot of ads for carbon steel pans. The most common descriptors that I see are along the lines of: It’s like a cast iron pan, but lighter and more responsive like the non-stick pans you’re used to. The seasoning even makes it mostly non-stick!
Like a sucker, the ads got me interested and I even got a steel pan for Christmas last year. It’s a pretty good pan! But it’s not non-stick or inert like a PTFE coated pan. I have cooked eggs in it a few times and it’s definitely not as easy as a non-stick pan. I also have to think ahead of time if there is any sauce or acidic foods going in it. I have still stripped and had to re-season it a couple of times. Overall it’s a good pan. I’m going to keep using it, and I’m not sure that I would buy another PTFE coated pan. However, I think my biggest complaint about the marketing of steel pans is the comparison of a “naturally” seasoned pan against the toxicity of PFAS.
First off, PTFE is incredibly inert. It doesn’t react with most acids, bases, or solvents, and it even outperforms glass labware in a lot of categories. Safety data sheets (SDS) for PTFE are essentially free of any hazards. Mostly it is flammable when in powder form, but the health effects and exposure controls are essentially none. The real hazard is the precursor chemicals used to make PTFE. The common ones were PFOA and PFOS. They’re both accutely toxic and corrosive, but the SDS does not have as scary of handling requirements as you might expect (PFOA: 1, 2 PFOS: 1, 2) They have the LD50, handling procedures, and that they’re listed as carcinogenic, but not nearly the severity you’d expect from something where a few ppb is harmful.
PFOA and PFOS have been phased out in most places, but a few of the replacements carry similar warnings and classification levels in their SDS (PFNA, PFBS, PFHxS, HFPO (1, 2), HFPO-DA) I don’t want to go crazy on the alternatives but those are a few that seem common. There were fewer open access publications I could find on the contaminant level safety on newer chemicals but they appear to still be bad. The overall bad chemical substitution process reminds me of BPA, which got phased out of polycarbonate production only to find out that the BPS and BPF used as replacements were likely just as bad or worse. A chemical that has to perform the same function probably has similar structure and functional groups, so it’s probably going to interact similarly with our bodies and the environment. I am not surprised if the effects are similar. Back to PFAS, an Australian university has a review paper with a more dismissive view of PFAS health effects. Humorously, another review saw the highest concentration of landfill PFAS leaching at a location in Australia.
As for the exposure from using non-stick products, it seems like it may be similar to what we’re already getting. Some LC-MS systems for measuring trace chemicals (like PFAS) have PTFE components in them, and pick up PFAS leaching if not corrected. The concentrations leaching in these machines are similar to the levels being proposed as limits for drinking water. However the conditions in an LC-MS column and a skillet are probably quite different and I can’t say if one would leach more than another. Considering we can’t avoid drinking, I’m not too concerned with cooking in a non-stick pan. I think the real risks come from the manufacture and disposal of the PTFE. Luckily, I still have my non-stick cookware, and plan to keep it until it’s worn out. With the steel pan hopefully I can re-season it forever and never need a new pan!
Luckily I see a lot of other products like outdoor clothing are avoiding the whole family of chemicals and labeled PFAS free. These SDS don’t have the same carcinogen listings and the toxicity is less, but there’s a lot more “effects unknown” so they could just be new and lacking the appropriate study. On the other hand, there are a lot of silicone and acrylic polymers out there that haven’t caused terrible concerns yet. I don’t know that heat tolerance of a non-stick pan will allow it to be one of the products getting substituted out with a silicone or acrylic, but maybe there’s hope for another option for the people who want to keep with non-stick.
But that was a lot of build-up to what bothers me about the advertising of a seasoned pan. They can sell you a non-toxic pan because you’re doing the toxic part by seasoning it at home! The majority of the steel pan advocates and advertisements mention that seasoning the pan is polymerizing a layer of oil onto the pan. It sounds cool, but I think there’s a difference between the controlled polymerization with monomers and a chemical activator, and uncontrolled polymerization. We’re talking about heating an oil until it breaks down, becomes reactive due to the unstable structure, and reacts with other oil molecules in an uncontrolled way. Those reactive molecules and random products can be hazardous!
The dangers from cooking oil fumes are primarily associated with polycyclic aromatic hydrocarbons (PAH), also some of the concerning compounds when dealing with grilled meats . Like PFAS, PAH is a huge class of chemicals. BaP is one of the most concerning PAH. The SDS for BaP are more definitive that it is carcinogenic than the SDS for the PFAS chemicals. The levels of BaP in cooked food is orders of magnitude higher than what are allowed levels in EU drinking water although the levels in kitchen air are orders of magnitude lower than the exposure limits on the SDS. More frequent cooking over high heat is correlated with higher incidence of lung cancer, although their maximum exposure category was >200 meals per day-years, equivalent to cooking at least 4 times per day for 50 years. I’m not sure why the kitchen air quality studies are all in China, or why some of them are so specific to put it in the title as if cooking food is fundamentally different in other countries.
PAH do accumulate, particularly in fatty tissues, but they also get metabolized and excreted which is better than PFAS. (But also some of the metabolites in the process cause cancer) PAH are considered a persistent environmental pollutant like PFAS, although definitely more from coal, petroleum refining, and smog than cooking at home. Since there are industries with orders of magnitude higher exposure than the kitchen (and mostly still well below the current permissible exposure limit for BaP) it seems that the risk of seasoning a pan is considerably lower than producing a non-stick pan.
To close off with some more general “heating your food is bad for you” browned potatoes (french frys, chips, hash browns, etc.) have been known for a while to contain acrylamide that is considered carcinogenic. Some recommend using potato peels to help with seasoning carbon steel. They don’t give a reason why to use this method, but maybe it’s to help regulate the temperature when seasoning on a stove instead of in the oven. Luckily it seems like acrylamide doesn’t get incorporated into the oil, at least when frying.
So I guess my takeaway is that seasoning a pan is not that bad. I’m still annoyed by calls to “get rid of your toxic pans and buy this carbon steel one instead” because a non-stick pan you already have is damage to the environment that’s already been done. The finished product is probably as safe as anything you’re eating or drinking in terms of chemicals you can get from it. There’s no point in disposing of it until it is actually damaged or no longer functional. I didn’t get rid of any pans when I got the new one, so when I really need the non-stick pan, I guess I will have it for a while!