Hacker News Reader

Comment by gumby | Hacker News Reader

I once got into an argument with a coworker about the non-reactivity and biocompatibility of PTFE (Teflon). What a fool: I had worked with the stuff on medical devices at a previous startup.

In any case out of annoyance I swallowed some teflon plumbing tape. A few days later I had to take an international flight and, ta-da, excreted it in the aircraft toilet. That was lucky as I had a convenient metal shelf and not a bowl of water. As I had predicted it was intact and perfectly white.

I sent my colleague a photo from my phone. He was annoyed when I got home.

PS: I had been carrying around a cheap disposable pen for this purpose. I stole it from his desk.

View on HN

That's enough Hacker News for today. You people are already acting Hacker News.

I can't think of any possible reason your colleague would be annoyed with a photo of your excretions in an aircraft toilet.

Not as annoyed as the TSA agent knuckle deep in you worried about a wrap being undone internally.

> I sent my colleague a photo from my phone. He was annoyed when I got home.

Did you...clean it off? Or just take a picture of it in the bowl along with the rest of the contents? I'd like to think I could the former, but if one of my coworkers sent me a picture of their faeces, annoyed wouldn't even begin to describe how I'd feel. Being completely incorrect on a technical matter, even foolishly so, isn't anywhere close to warranting being treated that shitty (pun fully intended but unfortunately not enough to mitigate my disgust at the idea of being sent a picture like this from a collegeaue).

A few *days* later? I guess I don't know the expected intestinal transit time for teflon tape.

So it emerged white. Firstly, that seems odd. Secondly, how do you know no particulates were shed inside you? Surely just eyeballing it isn't going to tell you much?

> So it emerged white. Firstly, that seems odd.

I think it would be odd had it not emerged white. It was white thread tape (I've never seen any other color). And it's not like it should react with the contents of my bowel.

> Secondly, how do you know no particulates were shed inside you? Surely just eyeballing it isn't going to tell you much?

You're right, except that I already knew the answer: as I mentioned in my comment I'd already used PTFE in a previous job; I've dissected and otherwise processed innumerable tissue samples from animals injected with various biocompatible polymers in the process of preclinical studies. Teflon is quite common in implanted medical devices for the very reason that it is safe and doesn't tend to break down.

Some polymers are considered safe but clear from the body through mechanisms nobody has worked out. For example the polymer fillers some people have injected to push out wrinkles are, as far as I remember, a safe mw of PEG that just seems to...go away.

I've used PEG as a drug carrier but have used the drug to determine how it was breaking down (or microscopy), rather than trying to assay the carrier itself. FDA is super concerned about the API (i.e. drug) and most excipients, but for a neutral GRAS carrier like PEG. meh. Though they do care a lot that you make sure the mw is in one of the GRAS ranges!

> It was white thread tape (I've never seen any other color).

Teflon tape for gas connections is yellow.

Is there any particular reason?

From the packaging, it says it's more dense. The yellow color is used to indicate gas, so I suspect that's why they chose yellow.

Yellow is thicker and required by code to be yellow so it's visually distinguishable from the plumbing version.

There’s also blue colored as well. Blue Monster brand.

I have some that's pale pearly gray. Not sure if they just cheaped out on a colorant or something, but it's definitely bargain-basement stuff so that wouldn't surprise me.

edit: Or maybe it's for stainless steel pipes?

There's also a pink for 1/2"- 2" waterlines and sprinklers, green for oxygen lines and grey for stainless steel pipes.

So this was less of an evidence-gathering exercise and more to emphasize how sure you were?

Is it possible that your co-worker was annoyed mostly because nobody really wants a picture of poop?

I assume he was annoyed entirely because he did not want a picture of poo, but knew I’d sent it legitimately!

> I think it would be odd had it not emerged white. It was white thread tape

You seem to be implying that it also was white when it went in? This wasn't stated in the parent post. But in that case, emerging white, same as when it went in, is a good outcome.

Teflon plumbing tape is universally white so I figure he figured that was enough to communicate that it was white going in.

Firstly, "it's always white" is domain-specific knowledge that most of us don't have. I've seen the white plumbing tape for sure, but I didn't make universal assumptions based on that.

Secondly, another comment gives examples of similar tape that isn't white. https://news.ycombinator.com/item?id=34554613

> Firstly, "it's always white" is domain-specific knowledge that most of us don't have.

How is common home repair supplies count as "domain-specific"? You don't have some teflon tape in a storage drawer somewhere in your house? Have you never replaced a faucet aerator or shower head?

As to the other tape, that's apparently for gas connections (I've never of it personally) when the original poster specifically specified plumbing tape.

I don't have a roll of the stuff, no. I've seen them. I've seen plumbers use them. And I've changed a couple of shower heads, but I haven't used it.

So, I'd file this under "one persons experience is not necessarily a guarantee of universal experience."

> You don't have some teflon tape in a storage drawer somewhere in your house?

Probably, I'd have to look. But like I said "the last one that I saw was white" is one thing, "it's always white" is another very different thing. Is this a standard that it _has to be white_? If you can't answer that, then you have no case at all that it's not "domain specific knowledge".

So.. does that mean there isn't actually anything to worry about with teflon pans? I've certainly heard claims that you can end up with particles in your food, which is bad somehow. Seems unlikely there's evidence behind that given that the pans are still sold, but then, plenty of dangerous things are. Sounds like even if it does flake off in your food, no big deal? Or can cooking it make it into something more reactive?

Have a look at this Ted-ed video [0]. What they basically say is that Teflon is not dangerous in itself, what is dangerous is the product they use to glue it to the pan.

[0]: https://youtu.be/uXaP43Zbz7U

If manufacturer has convinced regulators that Teflon isn't dangerous just because the danger is in something that always has to be used with Teflon and not Teflon itself, surely that's criminal?

Only if it’s still present in the final product.

It’s not uncommon in chemistry for two very reactive elements/compounds to combine into a molecule that is very stable and relatively benign.

Sodium and Chlorine == table salt, for instance.

Another example - Aluminum is pretty safe to be around, especially if it’s anodized.

Anodized aluminum is even perfectly safe for use as a pan for cooking pretty much any food.

Non-anodized is decently safe, just don’t use it with acidic foods. It’s common in large commercial cookware, though stainless is steadily replacing it.

You really don’t want to be exposed to the chemicals used to refine aluminum or anodize aluminum though, as they include fluorine gas, chromic acid, etc.

Same with titanium, stainless steel (albeit stainless generally doesn’t need a secondary coating), etc.

[https://en.m.wikipedia.org/wiki/Hall–Héroult_process]

[https://en.m.wikipedia.org/wiki/Hoopes_process]

[https://www.anoplate.com/finishes/anodizing/]

If you overheat it (which might happen if you leave the pan on heat with no contents, or you’re trying to cook something like steak at high heat) then it breaks down into a fairly nasty gas which is fatal to birds and gives humans flu like symptoms (exact health effects of this aren’t known).

And as other people have mentioned, the manufacturing process involves some really nasty chemicals, which often end up leaking out into the environment.

Adam Ragusea made a great video on the subject: https://youtu.be/5FNNKhVoUu8

"Secondly, how do you know no particulates were shed inside you?"

It's PFAS, so he likely got a high load of forever chemicals that are still in him today.

Can anyone explain why this is voted down?

It seems likely to be true based on a lot of compelling evidence. What am I missing?

Even if the tape appeared unchanged during transit of the GI tract, fragments of it could have detached from where it was damaged from being cut or torn from the roll. These fragments appear to make their homes in our bodies.

Teflon is not a dangerous PFAS. That's why it's downvoted.

Also no, Teflon cannot stay in your body. It's not available for biouptake. The non-reactivity of Teflon is it's entire point.

This is why Teflon coated pans are safe. You can break off pieces of it and consume it and it will be guaranteed to pass through your body.

Also further, "PFAS" has been turned into a buzzword when in fact it groups a huge number of chemicals, some of which are quite dangerous (and largely already banned) and some of which are completely safe. If you just say "PFAS" it's clear you don't actually know what you're talking about.

Fluorine is toxic. I don't care if you bind it to carbon and think it'll probably never break bonds in the vicinity of humans. Get that shit away from me, and especially don't coat my cookware with it!

If you think fluorine is toxic in any compound, let me tell you about dihydrogen monoxide. It’s found in over 90% of human tumor cells, and of course serves as a solvent to bring ionized fluorine into the body.

Hydrogen and oxygen aren't toxic (to us).

So you would have no problem drinking high concentration hydrogen peroxide?

Or breathing pressurized oxygen for that matter? Have a look for oxygen toxicity on Wikipedia.

"This atom is toxic, this one isn't" isn't how chemistry works.

You are not responding to the best possible interpretation of my comment. It is obvious that literally everything in sufficient quantity will kill you.

I would rather drink a quantity of hydrogen peroxide, than an equal quantity of fluorine. Also, hydrogen peroxide is a compound, fluorine is an element.

I would rather breathe pressurized oxygen, than pressurized fluorine.

The lethal dose for hydrogen peroxide is 40 times that of fluoride. Think about a glass of hydrogen peroxide. Now imagine 1/40 of that, a tiny bit at the bottom of the glass. That's an equivalent amount.

You've refuted nothing.

You’re whole argument is nonsensical. Do you avoid cherries because of the cyanide?

> I would rather breathe pressurized oxygen, than pressurized fluorine.

Dead either way. Why would you have a preference?

You’re arguing into the void here, against a poster who fundamentally doesn’t understand chemistry.

This poster got perfect scores in all chemistry exams in high school. Since you've vapidly ad hominem'd me on authority, now let's hear what makes you the chemistry expert.

It’s kinda hilariously obvious. Compounds have different properties than their elements. Fluoride ion are safe enough to use in toothpaste, and protect teeth in fact. CFCs replaced ammonia as a refrigerant, because it is much much safer and inert in the absence of high energy photons. We still use HCFCs, and the F in there is for fluorine-carbon bonds.

The health effects of Teflon decay (only by overheating, really) are not caused by fluorine. They are caused by the decay products, tetrafluoroethylene and difluorocarbene. This has nothing to do with the fluorine part: you get symptoms of poisoning 4-8 hours later from those vapors, not like the immediate chemical burns of fluorine gas.

Compounds are just plain different than their elements. Mercury is pretty bad for you, but you could swallow a pure sample of mercury sulfide and nothing would happen to you. You have a little knowledge of chemistry but haven’t internalized the theories.

Also: good test scores in high school means you’re a perfect candidate for Dunning-Kruger. Anyway your internal model of chemicals is as a collection of atoms which are kinda like Legos, instead of thinking of bonds and electrical fields.

> Do you avoid cherries because of the cyanide?

Of course. I also deliberately do not eat apple seeds for the same reason. Do you actively seek to eat toxins?

> Dead either way. Why would you have a preference?

Because one is more likely to kill you than the other. I don't know why you're making this out to be so complicated.

I can't live my life avoiding oxygen. I can live my life avoiding fluorine. Simple as that.

> Also, hydrogen peroxide is a compound, fluorine is an element

That's my point: compounds can be poisonous, but the toxicity of an element depends on the compound it's in. PTFE is a compound that's non-toxic. It just doesn't react with anything in the body.

Carbon and fluorine form a really strong bond. This is both why F2 reacts with so much, and why PTFE reacts with so little.

Hydrogen doesn’t cause toxicity in our bodies but I’m fairly sure oxygen does quite readily.

Water does as well. Many people experience mild forms of water toxicity, and although it’s rare, it can be fatal too. Oxygen is pretty dangerous stuff, you really do need to moderate intake and allow buffers in your body from having too much of it.

Sure, unless you overheat your pan...

Also it's ironic how the person who successfully proved how Teflon goes unprocessed by body's food processing has internal organs and blood full of PFAS that is pumped into the environment as a byproduct of Teflon manufacturing.

Overheating a Teflon pan is pretty difficult to do, and even then it's not like it suddenly exposes your body to dangerous chemicals if you continue to use the pan after it's been overheated once.

It's not that difficult to heat the pan to 280 degrees by accident, which is all that's required, no? At that point you feel sick and your pet birds start to drop dead.

Note I said "after". And you'd have to leave it at 280 degrees for quite some time to get the temporary effects. Some good ventilation and taking the pan off the fire will end the effects.

If I'm remembering the statistics correctly, despite the millions of Teflon pans in the US, there is less than 1 case of people getting Teflon flu from cookware per year. It's just not something that happens. Lightning strikes humans more often.

The probability of me leaving pan on high heat by accident: high, done this multiple times. The probability of me reporting any sickness as teflon flu: zero because I had no idea that Teflon could cause anything like this until yesterday when I looked this up.

And we don't know anything about long-term effects.

Anyway it's pointless because no matter how safe teflon is the side products of its manufacturing should already be enough of concern to render it illegal but somehow no one cares

"If you just say "PFAS" it's clear you don't actually know what you're talking about."

That's funny, because clearly you don't know what you're talking about, or how PTFE is made.

I never said the PTFE was the problem. PTFE was manufactured using PFOA. DuPont replaced PFOA with GenX. We know PFOA is linked to various health concerns. We don't have much info on GenX, but the EPA has issued cautionary guidelines on potential health impact.

https://phys.org/news/2022-10-teflon-coating-hot-microplasti...

What harms might result from the ingestion of tiny bits of Teflon is something I suspect will be much more closely looked at now that we're learning more about the effects of microplastics and PFAS on the body. While we wait for science to do its thing, the more immediate concern is Polymer Fume Fever (https://www.fireengineering.com/firefighting/engine-company-...). Breathing PFIB sure seems like something best avoided. You can always keep a bird around like they did in mines. If your canary dies in your kitchen maybe open a window.

Folks should absolutely go ahead and snack on teflon if they want to, but where it's possible I see very little harm in taking a precautionary approach with PFAS, including teflon, especially considering DuPont's track record on deliberately and aggressively hiding known harms from the public and the environmental and safety concerns surrounding its production.

I suggest reading up on what Teflon is. Teflon cannot stay around in the body. It's safe.

I have a question, is PFAS still persist in processed PTFE? From what I read, the concerns are mostly with the manufacturing rather than the safety of the resin itself.

Yes, it is still found after processing. That's the main reason they replaced PFOA with a different PFAS - GenX. They did this so they could continue to coat cookware after PFOA was being banned by the FDA.

Impressive dedication to science.

Thanks! I prefer to think of it as pettiness or peevishness. I knew there would be no risk.

>> I knew there would be no risk.

...as long as the plumming tape was made from Teflon, and nothing else.

I assume the majority of the most important science humans have done was to win an argument or impress a woman (or, more rarely but more notably, a man).

Mostly men, for tenure or boasting purposes. Until quite recently women were excluded from science, as they were excluded from so many other interesting things.

Depending on how reductionist you want to get (and if you're anything like me, that's quite reductionist), most everything we do is at least tangentially associated with impressing a mate.

Both criminals and scientists put in the biggest amount of energy into their "career" before they hit 30. Trying to impress a mate makes sense as an explanation. The peaking physical condition and declining Testosterone production after 30 might be another reason.

In the fashion of Barry Marshall. https://www.discovermagazine.com/health/the-doctor-who-drank...

Interesting, my mum did get her medical degree from that institution…

When my oldest was a baby, he swallowed a shiny star sticker. I found it in his diaper a day or two later, still shiny and still star-shaped.

I hope he recovered his pen.

Ha ha I should have considered that. Then again it could have led to an awkward situation while crossing a border.

I remember carefully depositing it into the rubbish bin of the toilet (the hinged door is always so small). And washing my hands really well.

> I had been carrying around a cheap disposable pen for this purpose

For what purpose? Picking out the PTFE tape?

Yes. What tool would you have used?

Civilized people use a poop knife...

I think the cutlery has to travel in the hold of the aircraft though.

Not on a plane you don't.

Unless the flight has a dinner service.

Gross.

Reply on news.ycombinator.com