Should a canary be mandatory in your kitchen?

[Bushmiller]

According to recent studies, keeping a canary in the kitchen may be adviseable if you are using Teflon coated products. I would expect that most of us have something that is non-stick in the kitchen.

We have deliberately chosen only stainless cookware, but we do have one of those sandwich maker/grill type devices, which we use for grilling steak and this has a non-stick coating. It appears that Teflon breaks down into some rather insidious products (primarily gases) at elevated temperatures. Dupont, the company that patented the name back in the forties, has been a little shy of warning it's customers of potential danger and a little vague when asked direct questions if you can believe the reports.

There is some discrepancy between the temperatures that Dupont maintain are critical and those that have been realised in independent testing. Birds are particularly susceptible to these gases and smaller birds more susceptible again. Back in the nineteenth century canaries were used in underground mines to detect the presence of poisonous gas. Perhaps we now need them in the kitchen.

Some reading for you if you would like to pursue it:

Teflon / PTFE (non-stock-coating) Toxicity

On why we sadly need canaries in the kitchen - news - *faircompanies

Is Teflon safe? (June 2006)

There are mountains of information when you start to delve into it.

Some while back I suggested to SWMBO that Teflon could become the asbestos of the 21st century: Extreme?

Regards
Paul

[doug3030]

I have found teflon to be grossly over-rated. You have to be ultra-careful not to scratch it, it can separate from the base utensil and is expensive beyond its benefits.

I dont have any teflon-coated appliances in the house. We have high quality stainless steel cookware and are very happy with them. They last forever and are robust and hard to damage.


Doug

[MAPLEMAN]

Very interesting reading Paul,thanks for the info..MM

[BobL]

I spent about 15 years of my working life working with Telfon laboratory ware (mainly beakers) including heating them to some pretty severe temperatures. I was always more worried about the stuff inside them like concentrated HF, HCl and HClO₄ , but maybe I should have paid more attention. One difference was we always used pretty strong fume hoods.

One thing I do know is that cooking oils that smoke at high temperatures (ie grape seed oil) should not be used in teflon coated pans.
Any smoking oil isn't exactly healthy for us either.
I guess that suggests that range hoods should be used in kitchen - maybe they should be wired in so that when the stove goes on so does the range hood.

[Poppa]

Don't like teflon either. We have enamel cookware in our kitchen and a beast of a cast iron frypan. But my wife imports and sells the enamel cookware, so we're not allowed to have anything else anyway.

[A Duke]

You will also note aluminium cook wear that was so popular about 20 years ago has quietly disappeared from the market.
Regards

[Gra]

My wife has often suggested a canary in our kitchen, but usually after I have cooked Mexican... Probably for a different reason though

[Bushmiller]

You will also note aluminium cook wear that was so popular about 20 years ago has quietly disappeared from the market.
Regards

Arthur

I was going to add that Teflon coated cookware is not the only thing to be aware of. Aluminium was OK until you started using a scourerTto clean it and then minute particle rolled around waiting to be absorbed with your food, but flouride's alright . The best thing I can say about aluminium is that it doesn't hurt anywhere near as much as when you are hit about the head with a cast iron frypan.

I really like cast iron and at home we have moved (back ) towards it in recent years, but I do have this slight hesitation about my well-being should I inadvertently make an indiscrete or ill-advised comment at a wrong moment in front of SWMBO .

Returning to the Teflon issue, my biggest gripe is that Dupont may have not have released their findings when they should. There is a parallel with the tobacco companies here and for that matter a once prominent Australian company who used to sponsor the Bathurst car race.

Overall the situation is not good and almost anything that is non stick comes under a cloud rightly or wrongly.

Regards
Paul

[Bushmiller]

One thing I do know is that cooking oils that smoke at high temperatures (ie grape seed oil) should not be used in teflon coated pans.

Bob

Olive oil (which I guess is a grape), and ordinarily considered healthy, should not be overheated. We don't use it in that way.

Regards
Paul

[BobL]

Bob

Olive oil (which I guess is a grape), and ordinarily considered healthy, should not be overheated. We don't use it in that way.

Regards
Paul

Olive is not the same as grape. Grape seed oil is a high smoking point oil whereas olive oil is not.
The significant thing about the smoking point is most people will tend to keep the temperatures of their cookware below this point.
High smoking point means the oil does not break down as easily at higher temperatures which is healthier but it also means it is able to heat any teflon coated stuff to a higher temp which is not so good.

We use grape seed oil on the BBQ (Cast iron) or on SS ware but only olive in the one teflon coated frypan we have left.

[Master Splinter]

There is no risk to end-users of teflon coated products in normal use.

The risk comes in the manufacturing stage, which uses a chemical called perfluorooctanoic acid (or PFOA), and the US Environmental Protection Agency has labelled PFOA a potential carcinogen. DuPont paid US$300 million as an out of court settlement to residents near one of its manufacturing plants because of exposure to PFOA.

The point at which the teflon on cookware starts to deteriorate is 260C; and it decomposes above 350C.

As the smoke points of most common oils are around 170 to 220 degrees by the time your teflon even begins to degrade you've already got a kitchen full of oil smoke which contains all sorts of nice, possibly carcinogenic compounds (such as acrolein) anyway.

Acrolein is toxic (it's used as a herbicide and algaecide) and a strong eye/skin/mucal passage irritant, and is also found in cigarette smoke. It is a suspected carcinogen. Acrolein is a major cigarette-related lung cancer agent: Preferential binding at p53 mutational hotspots and inhibition of DNA repair

[BobL]

Perhaps a worse problem is when oils are not being used. If a teflon coated sauce pan boils dry it can easily get to teflon thermal decomposition temperatures. This happened to us at home 35 years ago, luckily no one was home at the time and the fumes had largely dissipated by the time we got home but the acrid smell hung around for weeks. I recognised the smell because I had done a similar thing at work with a 500 mL solid teflon beaker and even though it happened in a fume hood I'll never forget the smell.

[Bushmiller]

Master S

Thank you for the extra information.

One of the problems I have with multi-national companies (and I freely admit, it is a prejudice ) is that they don't always disclose all the information they have to hand probably for commercial reasons. Unless you have some inside information or a thorough understanding of the chemical processes involved and indeed what is even a harmful substance in the first place we carry on in blissful ignorance. This is from one of the sources I mentioned earlier:

On one hand, DuPont maintains all Teflon-coated cookware is safe because none of the PFOA used to make Teflon remains in the finished product. On the other hand, DuPont acknowledges that heating empty Teflon-coated pans releases toxic fumes, but only at temperatures exceeding 660°F (340°C). There is currently a class-action suit filed by several states claiming Teflon releases PFOA under normal cooking use and that the company did not warn consumers about its dangers.7,9

Independent tests show that preheating nonstick cookware can raise the temperature to 736°F in three minutes and 20 seconds. DuPont's own tests indicate Teflon off-gases toxic particulates at 446°F At 680°F, Teflon pans emit six serious toxins. Coated drip pans easily reach 1000°F, at which temperature, the coatings break down to a chemical warfare agent (PFIB) and phosgene (the chemical analog of a WWII nerve gas).3,7

Studies show that when used on conventional stoves, Teflon chemicals break down into dangerous particulates and gases, including two chemicals linked to cancer or tumors in lab animals (PFOA, TFE), two potent global warming gases (PFB, CF4), two chemical warfare agents (PFB, MFA), and a chemical analog of WWII nerve gas, phosgene (COF2).3

The extent of non-stick surfaces goes beyond the ubiquitous frypan, although I concede it is the first kitchen utensil that comes to mind. In our case our sandwich maker is rarely used with oil. A self-cleaning oven will incorporate Teflon.

In some ways I am surprised that the elevated temperatures at which Teflon emits noxious or harmful gases is so easily achieved. There is also an issue that Teflon once the surface becomes damaged becomes more prone to an exfoliation type process that results in similar health issues. Another concern is for people who smoke cigarettes (I knew it was a good move when I gave up aged eleven) as they chemicals have a propensity to combine.

These are some of the chemicals alleged to be given off by Teflon:

Studies show that when used on conventional stoves, Teflon chemicals break down into dangerous particulates and gases, including two chemicals linked to cancer or tumors in lab animals (PFOA, TFE), two potent global warming gases (PFB, CF4), two chemical warfare agents (PFB, MFA), and a chemical analog of WWII nerve gas, phosgene (COF2).3

When nonstick coatings are heated during normal cooking, a complex mixture of gases is produced that changes composition relative to temperature changes. Lacking adequate human studies, the following information is extracted from animal studies:
• 464°F Teflon produces toxic ultra fine particles, causing severe lung damage to rats within ten minutes of exposure and death at longer exposures.

• 680°F Tetrafluoroethylene (TFE) causes cancer in lab animals (tumors of the kidney, liver, and a form of leukemia). It is a suspected human carcinogen.

• 680°F Hexaflouropropene (HFP) exposure may cause eye, nose, throat irritation; irregular heart rate, palpitation; headaches, lightheadedness; fluid accumulation in the lung (edema); and possibly death. Exposed workers may experience decreased memory, learning, and motor skills. Inhalation of HFP by mice and rats causes decreased number of lymphocytes (type of immune cells) and increased urination. HFP promotes chromosomal abnormalities in hamster ovaries. (HFP is sometimes added to pesticides as an "inert" ingredient.)

• 680°F Trifluoroactic acid (TFA) has caused decreased growth of fetal rat bone-forming cells (osteoblasts) and cartilage cells (chondrocytes), and neural tube defects in rat embryos. TFA is toxic to plants, and it is persistent. Long-term environ-mental impacts remain unknown.

• 680°F Monofluoroacetic acid (MFA) is extremely toxic and lethal to humans in doses as low as 0.7 to 2.1 mg/kg. Exposure may cause nausea, vomiting, tingling, muscle twitching, low blood pressure, and blurred vision. High exposure is associated with irregular heart rate (ventricular fibrillation) and heart attacks.

• 680°F Perfluorooctanic acid (PFOA) never breaks down in the environment and has become ubiquitous in the blood of Americans. It is very toxic to rats and monkeys. In rats, PFOA causes tumors of the liver, pancreas, mammary gland (breast), and testes. It also decreases thyroid hormone levels.3

I am not a chemical engineer and I have to say I have not checked the sources extensively. There does however appear to be a considerable amount of discourse on the net on this subject and not all of it is even particularly recent. The two exerts above are from 2006.

I have highlighted the problem for discussion. I suspect in our household we will be discarding the sandwich maker and removing the self-cleaning panels of our oven.

Regards
Paul

[BobL]

Paul, if you ingest teflon it will pass straight thru as it will not dissolve or break down in any digestive juices. The most concentrated acid in the human digestive system is strong hydrochloric acid but telfon will withstand acid 10,000 time more concentrated than this under pressure at 150ºC for many weeks and not bat an eyelid. I've had some forms of it up to 210ºC with a mixture of concentrated nitric, HF and perchorlic acid and it does not dissolve.

Bugger, while typing this I burnt some fish in the teflon coated frypan!!!!!!

[crowie]

About 25yrs ago when I was working in manufacturing industry, my engineered plastics supplier gave me a roll of "Tygaflor".
Basically glass reinforced industrial teflon sheeting for heat transferring and we have used it in cooking ever since [oven, grill & BBQ].
Now Paul you've got me concerned about using this product??
It's similar to the product on this website - Cammthane : Tygaflor
Cheers, crowie