This came up in another thread but needs a separate discussion. Here we are on a science oriented astronomy board but often the myths fly in from other fields. If you make a claim such as Teflon produces toxic fumes, kills pet birds, and flakes off in your food to poison you, you really should

1) Be clear what you mean.

I thought it sounded a bit outrageous that teflon cookware was dangerous to birds. The post did say, "if overheated" so there was an attempt to modify the claim, but it still left the impression that common overheating would cause fumes to be emitted. So I went checking. I looked at both the Dupont site and the MSDS.

From the MSDS, (material safety data sheet), for teflon:
http://www.skylighter.com/msds/TELFLON%20MSDS.htm

From the MSDS of Woven Nylon Teflon Liner as an example that teflon is combined with other products that add to the problem:
http://www.camd.lsu.edu/msds/w/woven...flon_liner.htm

From the Dupont site:
http://teflon.custhelp.com/cgi-bin/t...er/std_alp.php
http://www.dupont.com/teflon/newsroom/bird.html

If you are talking about an accidental fire or near fire, I imagine lots of items will emit smoke and fumes that can be harmful to birds.


and, 2) Check your facts.

Again from the Dupont site:
http://teflon.custhelp.com/cgi-bin/t...er/std_alp.php

I realize the Dupont site might be a bit predjudiced. There were quite a few sites on google listing teflon as toxic to birds but I didn't find any of them to be referenced to any studies, nor did they mention what temperatures were needed. Again, the post with this claim did say 'high temperatures' so I don't want to understate that. But the claims that teflon cookware is dangerous really should be backed up with some scientific data.

I can't recall reading any medical literature that teflon flakes from pans were absorbed. The choice to use cast iron because one may not have had time to investigate teflon, or one doesn't believe enough research has been done is legitimate. But the auto pilot claim that iron, being natural, is better than teflon, being unnatural is not good science.

BTW, there is some early data suggesting excess iron may play a role in Alzheimers disease.

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Yah the birds was me. 8-[


The reason that i said that was thet every book on birds i have and every vet i have visited have warned me specifically about leaving a pan on the burner for a long time without anything on it and the bird nearby. I did not say it was harmful to humans in any way. I doubt it would be.

But you are right beskep. Other arisols do harm birds. Like most fumes harm them. It is just that most people do not think teflon will emit a gass if burnt at a high temp.

SOrry if i confused anyone and tyhank you very much beskep foir looking up that information. :-)


Dan

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Compared to humans birds are very succeptible to certain chemicals and fumes and exotic birds are even worse. Miners used to carry canaries in cages down in the coal mines with them to detect fumes. The birds died and the miners beat it quick to the surface. We have two parrots and are very careful where they are kept in the house and kept away from the kitchen area entirely.

I make no claims for the toxicity of the teflon that flakes off in your food as it's cooking. I just don't like seeing dark flakes in the food. I will admit that I haven't used teflon for years now, and that it has probably improved. However, cast iron, properly seasoned and properly used is just as non-stick as teflon anyway. And it lasts forever.
I did have an aquaintance, now deceased, who had a very gravelly voice since childhood, attributed to having been stuck in his highchair while a teflon pan on the stove burned. That's what he said. Don't know if it's true or not.

I received the same warnings when I acquired my parakeet, and I never had the feeling that it was an Urban Legend--it was always expressed quite specifically, and from reputable sources: "The fumes from an over-heated Teflon pan are toxic to birds, so don't plan on setting up your bird's cage in the kitchen."

This warning is usually found in the bird magazines addressing the issue of working bird owners who desire "quality time" with Tweety in the kitchen after they get home, while they cook supper.

In school we were taught that iron was quite toxic by itself and tha twas part of the reason for the formation of the heme group. Yes/No/Maybe so? I actually still have the powerpoint lecture notes from that Biochemistry class on my computer.

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Inspected by #13

Now this is scary. But I'm thinking of my mother (age 87), her very recently deceased twin brother, and her older sister (age 90) who all grew up using cast iron, and are still using it. And all are still pretty sharp. I've got to go with the odds--at least the odds for my own family.

They are all repeating each other, based on a hysterical press release some years ago -- same as the mindless promulgation of the "need' for "8 glasses of water a day." Any hazards in the kitchen stem from the use of household cleaners, badly adjusted gas stoves, and poor ventilation. My cockatiel spent 20 happy years in a corner of out kitchen (typical lifespan is 15 years). He was moved only when we used oven cleaners and the like. Obviously, that one sample does not constitute a valid proof, but I am aware of many happy kichen-dwelling birds with long lifespans. As with so many things, common sense is a good guide.

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Standing on the shoulders of giants...

I'm not up to speed on any iron/Alzheimer's suspected connection, but there was a similar scare re aulminium/Alzheimers in the 70s/80s. Despite the fact that it was totally disproved, it lives on today in "health" magazines and on the net. Not too long ago, our dear Martha Stewart, guesting on a PBS radio show, warned people not to cook food in aluminium foil because of the dangers of Alzheimers; needless to say, a note to the radio show producers did NOT result in a retraction.

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I would only add that macroscopic pieces of polytetrafluoroethylene (PTFE, Teflon) have to be among the most chemically inert things ever made. I would unhesitatingly eat some (I mean, if I had to, not just because it tastes good). The carbon-fluorine bond is among the strongest covalent bonds around and no stomach acid or enzyme is going to break down PTFE.

Now, burning any fluorine compound or heating it above decomp temp will release nastier stuff, as pointed out earlier, perhaps the worst being hydrogen fluoride. HF is particularly bad because it can cause nasty burns and tissue necrosis, but the effect isn't immediate, like, say, nitric acid.

I was about to say that the amount of PTFE on a typical pan is so small that the total amount of possible HF release would be miniscule, but I'm going to hold on that for a bit. Let's see... to a rough approximation, PTFE is about 75% fluorine by mass (assuming basically CF2 repeating units in the polymer). Molecular weight of HF = 20 amu. So if there was 1 gm PTFE on the pan and you burned it all (quant conversion of all fluorine to HF) you get about... 35 millimoles HF... roughly 0.7 liters gas at STP....take a small, poorly ventilated kitchen, say 10x12x8, about 1000 ft^3, which is about 16,000 liters... or about 1 part in 20,000 HF , about 50 ppm, again assuming 1 gram PTFE coating, complete conversion of all Fluorine to HF, complete mixing and no ventilation.

I have a hunch the total coating is closer to 100 mg, but in reality it doesn't sound like a real situation could produce much HF, unless you hold your face right over the pan and inhale.

This is all in my head on a Sunday night, though.

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mike alexander wrote

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Standing on the shoulders of giants...

Very good responses. I'm glad you are all thinking these things through a little more carefully than the other thread suggested.

The iron and Alzheimers research was, to my knowledge, only suggestive and no where near conclusive. I only wanted to make the point that 'natural' was not the eqivilent of 'safer'. As to aluminum, I have avoided it when convenient only because I haven't had time to look into its risks further. I use it when it is the only clean pan left, (maybe occasionally :wink: ).

Iron makes wonderful cookware, Gethen, if you have the time to properly maintain it. And, any risk of excess iron has not been established. In addition, even if a risk is established, cast iron cookware has not been implicated. I have only recommended that my female patients past menopause not take extra iron fortified vitamins unless they have been anemic on blood tests.

But there are plenty of 90 year old smokers, that doesn't mean smoking isn't hazardous.

I also found a large number of references that teflon was a potential bird hazard, Humphrey. But when I looked at the citations more closely, I found they were mostly lacking references.

google search:teflon toxic birds

Also, I think I remember something about teflon heated to high temperatures made a compound that would be extremely unlikely to biodegrade. I didn't have time to look for the facts. I can say I have burned popcorn to a black gooey crisp in my teflon pan twice, and the pan is still non-stick, it hasn't flaked, and I still use it. My finches didn't die and they were in the dining room off the kitchen. Though the smoke was higher than the cage.

I think the two main points I took away from my quick search for data was the high temperatures needed to produce toxins and the lack of absorption of Teflon from the GI tract. Mike's wonderful contribution clarified those two facts quite nicely.

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The lifetime of birds in the kitchen really depends on how well you cook 'em!

Martha is probably not too familiar with Foil Pack Cooking. We cook things in foil packs on Boy Scout camping trips. There are a great many different ways to cook in foil, both in your own kitchen, or out on the grill. I want to know when Martha is going to teach us to bake a cake with a file in it. It might come in handy someday soon. 8-[

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Do you think she was just doing a set-up so she could plead mental incompetence? You know, " I ate so much food cooked in foil as a kid that now I can't remember what I did about that stock sale."

Not much hope, unless she wants to prove that she doesn't know much biological science. The aluminium/Alzheimer link has been pretty well refuted. It stems from some very sloppy work in the 60s which showed aluminium plaque in the brain cells of people who dies with/of Alzheimers. People ljumped to the conclusion that an association was a cause, a common fallacy. Further research showed that the plaque was asscoiated with having Alzheimers, not with causimg it.

From the webpage of the UK Alzheimers Society:

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I would only add that aluminum metal dissolves in both acids and bases, that is, at pH levels several units away from neutral. Among the common foods tomatoes are acidic enough to dissolve some aluminum.

When exposed to air aluminum develops a thin oxide coating that is quite impervious unless scratched or exposed to pH extremes (astronomy here. an aluminized mirror is quite soft for a few weeks until the oxide coating forms).

Cooking neutral (pH-wise) foods in aluminum shouldn't pick up appreciable amounts of the metal.

Note that if you like your aluminum pots shiny and polish them up with the brillo pad, you are taking off any oxide coating.

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mike alexander wrote

Probably the cause of Martha Stewart's problems...............

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Standing on the shoulders of giants...

Anybody got a beef with copper? Just trying to figure out what to cook with. 8-[

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