That's honestly one of the things I wish we could get a handle on.
Company gets sued for using and hiding the danger of a compound they learned fairly quickly was toxic. Goes and invents another compound and switches to it without having to prove its safety. After it becoming public that they were intentionally hiding dangers for a half century, I feel we should take away their ability to be given the benefit of the doubt.
All I think they learn from these lawsuits is that they need to get better at identifying and removing people who will call them out on their bullshit.
Edit - I know the whole thing with DuPont was using PFOAs in the manufacturing process and leaking (intentionally dumping) them into the environment, but it's not like the final product (Teflon) is safe to ingest either, which as a cooking surface, you most definitely will in some quantity.
> but it's not like the final product (Teflon) is safe to ingest either
Sure it is. I don't think a less toxic material than Teflon even exists. It's toxicity is comparable to water.
The LD50 of Teflon is > 11,280 mg/kg. Water by comparison is 90,000 mg/kg. They were not able to measure the exact toxicity because it's impossible to eat so much.
Is LD50 a meaningful measurement for biopersistent and accumulated compounds? It seems like it would be quite useless, or worse, misleading.
I recall that large blobs of mercury was used as a homemade remedy for stomach issues which turned out to not be a great idea for obvious reasons, although it's LD50 would probably have been similarly high.
LD50 only tells you acute lethal toxicity. LD50 can be astronomically high and a compound might still have long term, non-lethal toxic effects like injuring specific tissues.
No one is even suggesting lethal toxicity is the issue here, so how is it relevant?
Bullshit. There is “toxic” and there is “causes cancer, even outside California, reduces fertility, and negatively affects fetal development.” Just because something doesn’t kill you immediately does not mean it isn’t harmful.
Even inert materials can do stuff, such as prevent other reactions or act catalytically or have physical impacts (collision which defold molecules, make certain things heavier by being enclosed or enclosing ... ).
Furthermore PTFE is know to interact with Gallic Acid [1] somewhat. The body contains gallic acid
I really appreciate you making the effort to debunk the witch-burners; have you thought about doing it in a less ephemeral medium? Your comment will probably be here for a decade or more but nobody will read it after this month.
But the claim in question is one of the best-known and most thoroughly established claims in all of toxicology. Asking for scientific research supporting the biocompatibility of PTFE is akin to asking for scientific research supporting biological evolution or the claim that people have landed on the moon: it's a sure sign that the person making the demand has a pre-existing flimsy pretext for rejecting literally all the research in the relevant field, which did indeed turn out to be the case; see https://news.ycombinator.com/item?id=32517203.
If it's truly such a well established claim it should be trivial to find and link a study actually demonstrating its safety when ingesting small amounts over a large period of time. No such study was linked. Probably because longitudinal studies are extremely rare.
It's not a rejection of all research to say that some questions remain unanswered. In fact, I'd say it is the foundation of good science to understand which claims are supported by evidence, and which claims are not.
There are half a dozen studies per year, going back decades, assessing the safety of PTFE in implants. Many of them are longitudinal. Chemists routinely boil PTFE in acids such as hydrochloric and sulfuric for hours without degrading it even slightly; such degradation would contaminate their reactions.
I bet you can't find a study demonstrating natural selection in the split-leaf philodendron, either, but that isn't a good reason to go around saying "some questions remain unanswered" about whether the split-leaf philodendron is an exception to the laws of evolution.
The two comment threads are the same discussion so I'm merging my responses.
> I bet you can't find a study demonstrating natural selection in the split-leaf philodendron, either, but that isn't a good reason to go around saying "some questions remain unanswered"
It absolutely is! The criterion for whether a question has been answered is whether that question has actually been asked, studied, and answered. In cases where there is no specific evidence, you attempt to make assumptions that extend existing evidence into spaces that it does not explicitly cover. But these aren't answers; they are educated guesses. Some guesses are better than others, and really the fundemental act of science is feeling out these hypotheses and deciding which ones are sturdy and which are shaky.
So for example consider the claim 'PTFE doesn't affect human health when ingested, because there is strong evidence that is safe in implants and is chemically inert in acids.' This claim relies on two assumptions in the absence of quality direct supporting evidence: (1) Safety in one biological context directly transfers to other biological contexts and (2) Chemically inert compounds cannot affect human health. There is mounting evidence against ~both~ of these assumptions, and so claims based on them should be treated with caution, and probably as warranting further study. This is no witch-hunt, this is simply using critical thinking and available evidence to gauge the validity of assumptions, and updating the validity of claims based on changes in the validity of underlying assumptions. This process ~is~ the scientific method.
> Nanometer-sized pores matter enormously, (...) but not in ways that make other forms of amorphous silica more toxic than silica gel.
Try replacing your morning cheerios with silica gel and let me know the results. The pores in silica gel are specifically interesting because they allow silica to readily form hydrates. The human body has a lot of water in it. There are absolutely health effects that depend on the physical shape of silica in addition to its chemistry compared to say, consuming an equal mass of fully dense quartz particles.
You'd probably have to eat a lot of silica gel to really feel the effects, but there are other more accessible and serious health concerns that are driven by nanometer or smaller physical effects. The reaction between diet coke and mentos is primarily physical, driven by nanometer-scale surface roughness on the candy. Proteins sometimes fold in abnormal shapes, and in the right circumstances, the presence of a chemically identical but differently-shaped protein can induce other proteins to change shape as well, leading to prion diseases such as Mad Cow and CJD, both of which can be acquired via ingestion of the trigger protein shapes.
The claim that nanometer-sized structural changes in a compound can have no effect on human health when ingested is demonstrably false. Obviously, this calls directly into question the dependent claim that chemically inert compounds can have no possible impact on human health when ingested.
Yes, you can dehydrate your tissues by eating dehydrated silica gel. But when hydrated it's a Generally Recognized As Safe food additive in quantities up to 3% (5% in the EU). You can probably eat a lot more than that but it will grind up your teeth. (By the same token, someone could strangle you with a PTFE cord, a fact that has no bearing on its toxicity.)
Quartz is not amorphous silica, and unlike amorphous silica, it's carcinogenic if you inhale it.
You don't get nanometer-sized structural changes in teflon by scraping it off your skillet with a spatula. You're being ridiculous.
I'm interested to hear what response you get from biologists when you propose to them that natural selection might be inoperative in the split-leaf philodendron. I imagine they'll wish they had a PTFE cord handy.
> Quartz is not amorphous silica, and unlike amorphous silica, it's carcinogenic if you inhale it.
Crystalline silica is still silica.
> You don't get nanometer-sized structural changes in teflon by scraping it off your skillet with a spatula. You're being ridiculous.
The words of someone who has not spent time analyzing electron microscopy of fracture surfaces :) It absolutely does without any possible shred of doubt. But that's not even the point; the point is that the fine physical structure of compounds can matter in biological systems. If you accept this, that it is plainly obvious that chemical inertness of a compounds is an obviously insufficent condition for safety.
> I'm interested to hear what response you get from biologists when you propose to them that natural selection might be inoperative in the split-leaf philodendron. I imagine they'll wish they had a PTFE cord handy.
If you spend a lot of time around people with science PhDs, you will quickly learn that most of us are keenly aware of how little we actually know and how much of it is guessing. Murdering people over disagreements is the domain of religions, not science. Sadly for many these two are interchangable.
And you think that ingesting PTFE is somehow worse than an actual PTFE implant? Why you insisting it must be a digestion study? Do you make such requirements for everything you interact with? Has someone done a study on using paper straws? Or plastic plates? Or metal spoons?
Do you understand that when you eat PTFE it comes out exactly the same way it went in?
Even powerful acids can't do anything to PTFE, what makes you think the body can do anything to it?
Titanium is a common biocompatible implant material, widely considered safe in this context. One of the primary benefits of titanium implants is that that they readily form a TiO2 passivation layer. TiO2 is also common in many topical lotions and sunscreen, where it is considered safe.
TiO2 also has a signficant body of evidence demonstrating that it is a carcinogen when inhaled in particulate form. Just because some compound is safe in one context does NOT mean it is safe in all contexts.
> Do you understand that when you eat PTFE it comes out exactly the same way it went in?
I bet if I asked you to eat shards of glass, they would leave your body pretty close to how they went in :) Whether your body would remain unchanged is another question. While this is an extreme example, there are more subtle ways a compound could interact with the body. For instance, glyphosate has long been considered a safe compound because it "leaves the body the way it comes in." However, recent research has revealed substantial evidence that glyphosate may adversely interact with the human microbiome, which is linked to many various health conditions. This is an active thrust of a lot of new medical research that wasn't strongly considered 20 years ago. It is simply not enough to say the compound remains unchanged, the real question is whether the body is unchanged, and the body is pretty complex and our understanding is very incomplete.
It's not clear which version of the scientific method you subscribe to from your posts, but in general proving a negative is ~really, really~ hard. This list of all possible interactions in the human body with arbitrary chemicals is quite long. The list of things that have been 'proven safe' only to be considered unsafe when studied more carefully is quite long. To suggest that our knowlegde of the safety of ~any~ compound is complete is impossible.
You're confusing TiO2 with SiO2. There is some interesting evidence suggesting that TiO2 nanoparticles may accumulate in the body, in particular in the pancreas, but there is definitely not a significant body of evidence suggesting that inhaled TiO2 is a carcinogen.
It would be pretty interesting if it turned out that TiO2 added to food as a white colorant were responsible for the obesity pandemic --- the epidemiological correlations are about right --- but so far the evidence that it has any kind of harmful effect at all is fairly weak.
Shards of glass are commonly used as a mild abrasive in toothpaste, an inert excipient in pill formulations, and a gas reducing agent in simethicone; they go by the name "amorphous silica" or "silica gel". They're also added to grains as an insecticide in the form of diatomaceous earth. It's commonly accepted by people who study this stuff that they are absolutely harmless to humans at that size.
What about larger sizes :) Physical effects can matter as much as chemical. Diatomacious earth has conflicting evidence anyway. Silica gel and glass aren't really the same thing.
I did mean TiO2. There is a reason the EU considers it a carcinogen and is banning it from several classes of products.
Silica gel is glass with nanometer-sized pores in it. Bottle glass has additional additives that lower its melting point and increase its solubility (oxides of sodium and calcium).
The EU has irrationally banned all sorts of things since the witch-burners have seized control of the government apparatus. Borate fire retardants and fertilizers is one of my favorite examples.
Nanometer-sized pores matter enormously, which is why we make silica gel in the first place, but not in ways that make other forms of amorphous silica more toxic than silica gel.
I'm not dismissing research that disagrees with me as witch-burning. I'm dismissing people who disagree with literally all the research.
> And you think that ingesting PTFE is somehow worse than an actual PTFE implant?
I think that it isn't even close to being equivalent.
> Why you insisting it must be a digestion study
You are the one who made the statement: "It's about the most inert material that you can possibly ingest." so prove it, or admit that this is your opinion and not backed by research.
I'm not even asking for research comparing the effects of the ingestion of PTFE with every other "material that you could possibly ingest", just for any data, at all, on the long term effects of ingesting PTFE.
It's my understanding that the toxicity of ingested PTFE is still an open question, that there is no consensus on the safety or dangers of Teflon in food, and no research into the effects of ingesting it over/after long periods of time (say > 20 years).
If you have actual knowledge of advancements in the science I'd like to see what was found, but otherwise let's just acknowledge that there is still far too much work to be done before we can make meaningful claims about the safety of ingesting PTFE. At best, what we can say right now is that it won't instantly kill you, but the long term effects of ingesting PTFE on the body are unknown.
You can't have a long term study given that PTFE doesn't stay in the system, so there's nothing to study.
Are you planning on feeding people PTFE every couple hours?
> the long term effects of ingesting PTFE on the body are unknown.
They are known. They are non-existent.
You are arguing from bad faith and profound lack of knowledge of chemistry. To even hypothesize that PTFE can do anything, anything at all, to the body would require some new magical chemistry that doesn't exist.
There is nothing in the body, nothing, that can affect the stability of the chemical bonds that make up PTFE - if you had even a tiny bit of scientific understanding you know that, and not embarrass yourself with these demands for studies.
Teflon in isolation may be fine, but your average cookware still contains enough PFOA left over from the synthesis process to cause harm. The replacement to PFOA (GenX?) has also been found in modern Teflon cookware as well.
Also, Teflon out-gasses at temperatures well below your average stovetop flame. Toxic enough that you can't use Teflon cookware if you own birds. It'll kill them.
Not necessarily; if it were oil they would notice the smoke, while the fumes generated by teflon are quite subtle until a much higher temperature. So there have been many cases where people killed their birds before noticing that anything was wrong.
While I'm totally comfortable with eating teflon, I'm absentminded enough that I've overheated cookware many times, so I wouldn't use it if I had birds.
It does not build up in your body, it builds up in the environment. The amount in your body is basically exactly the same as whatever environment you are in.
On top of that, how much PFOA would you imagine is even in a frying pan? It's already so little it's considered negligible, so unless you are buying new ones every day, even the negligible amount is not "building up".
> Yet that negligible amount is enough to kill birds.
No it's not. You misunderstood what you read.
To kill birds you have to burn the Teflon, and the Teflon smoke kills them. And you have the get the pan HOT - way hotter than anyone cooks. Teflon is not easy to burn, you can put a blowtorch on it for a short time and not affect it.
Company gets sued for using and hiding the danger of a compound they learned fairly quickly was toxic. Goes and invents another compound and switches to it without having to prove its safety. After it becoming public that they were intentionally hiding dangers for a half century, I feel we should take away their ability to be given the benefit of the doubt.
All I think they learn from these lawsuits is that they need to get better at identifying and removing people who will call them out on their bullshit.
Edit - I know the whole thing with DuPont was using PFOAs in the manufacturing process and leaking (intentionally dumping) them into the environment, but it's not like the final product (Teflon) is safe to ingest either, which as a cooking surface, you most definitely will in some quantity.