Original title: Your Teflon Frying Pan May
Be Causing Problems
Nothing may stick to Teflon, but new research suggests that
the byproducts of the heat-resistant coating may be sticking around in the
environment for a long time. Researchers in Canada have discovered that
heating Teflon -- the coating used in non-stick frying pans -- and other
similar compounds releases potentially harmful chemicals, including some
linked to the destruction of the ozone layer and others that may linger
in the environment for years and years.
The precise environmental and health impact of Teflon and
similar heat-resistant coatings is uncertain, but the findings suggest that
continued use of the compounds may contribute to the depletion of the ozone
layer and global warming.
After ozone-depleting compounds called chlorofluorocarbons
(CFCs) began to be replaced with alternative chemicals called hydrochlorofluorocarbons
(HCFCs) and hydrofluorocarbons (HFCs), scientists began to notice a rise
in levels of trifluoroacetic acid (TFA) in the atmosphere. It turns out
that as the alternatives to CFC degrade in the atmosphere, they produce
TFA, which persists in the environment over time and can be harmful to plants.
But based on the amount of HFCs and HCFCs being used, Dr.
Scott A. Mabury of the University of Toronto and colleagues realized that
there was too much TFA in the environment to have been produced by these
CFC alternatives alone.
Mabury's team suspected that some of the extra TFA in the
environment may be produced when Teflon and other so-called fluoropolymers
are exposed to high temperatures. Besides Teflon, other fluoropolymers are
used in ovens, engines, circuits and other devices exposed to extreme heat.
Heating Teflon and other fluoropolymers produces TFA and a
wide range of other chemicals. Some of these include CFCs, which destroy
ozone, and fluorocarbons, which may contribute to global warming by acting
as "greenhouse" gases.
Mabury noted that fluoropolymers also gave off larger versions
of TFA that, like the smaller version, do not degrade in the environment.
But it is possible that the larger compounds can make their way up the food
chain, Mabury explained, since fish can absorb the chemicals from water.
The Toronto scientist stressed that the findings need to be
confirmed and that the specific amounts of these chemicals released into
the environment need to be measured. Although regular-sized TFA does not
seem harmful to people, several groups of researchers are investigating
possible health effects of the larger versions, Mabury said.
Nature July 19, 2001;412:321-324
Research: David A. Ellis, Department of Chemistry, University
of Toronto; Jonathan W. Martin, Department of Envrionmental Biology, University
of Guelph; Derek C.G. Muir, National Water Research Institute, Environment
Canada, Burlington, Canada.
Dr. Mercola's Comment:
It appears that my cooking recommendations of suggesting that
Teflon coated cookware is acceptable may need to be modified. This research
makes it quite clear that one should not heat Teflon to high temperatures.
My guess is that at lower temperatures it is not as serious
an issue. I have used Teflon coated cookware prior to this study, but I
will clearly revise my use based on this research.
Dr. Paul Connett was gracious to provide a commentary on this
study and it is being posted below.
Comments from Paul Connett, PhD:
Teflon is the trade name for the polymer polytetrafluoroethylene
(PTFE) used in electrical insulating tape; combustion engines; chemical
apparatus and tubing designed to resist attack from most chemicals, and
in non-stick frying pans and other cookware.
Prior to this article there have been stories about caged
birds dying in kitchens after fires involving Teflon cookware, suggesting
the emissions of toxic gases when this polymer is burned.
This article is more serious because the researchers did not
burn the Teflon but simply heated it. Presumably, typical cooking procedures
would also heat the Teflon to the temperature range investigated by these
researchers. Thus, this material that is perceived by most as being benign,
could be a source of both significant indoor and outdoor air pollution.
This is another nasty indication that the world of organofluorine
compounds could be going the same way as their more famous cousins: the
organochlorine compounds. In the latter case most of these products, such
as organochlorine pesticides, solvents and PVC plastic (despite the toxic
generating manufacturing processes that produce them) were perceived as
However, they had several problems:
They tended to be very persistent in the environment
They are fat soluble and resistent to normal detoxification
processes in the liver
They accumulate and concentrate in animal and human body
They get passed on by the mother to the fetus through the
placental membrane and then to the infant via breastmilk,
A number of them are endocrine disrupting chemicals (i.e.
they interfere with the production or performance of hormones, which are
the messengers produced in special glands to regulate body chemisty) To
top it all, when these substances are burned in any facility ranging from
a back yard burner to a trash incinerator, they produce highly toxic byproducts
including dioxins and furans ( PCDDs and PCDFs).
Twelve of these compounds (or families of compounds) were
the subject of the POPs (persistent organic pollutants) treaty signed in
Stockholm last May by many countries around the world, including the US.
The bottom line is that nature doesn't make persistent things.
Both in our bodies and in the environment, natural processes are constantly
building up and breaking down all the chemical components used.
Nature attempts to protect itself from persistent fat soluble
substances by converting them to water soluble substances, which can then
be excreted through the kidney. If this strategy fails then they are stored
in our fat. In the case of persistent (or permanent) water soluble substances
like fluoride or lead, the body will excrete as much as it can through the
kidney and what it can't ends up largely in our bones.
However, in the case of both fluoride and lead other more
sensitive organs like the brain and pineal gland may also have mechanisms
which allow their accumulation.
Returning to organofluorine compounds, it is also interesting
to note that there are two forms of fluoride found in human plasma: free
(or inorganic) fluoride and bound fluoride. According to Gary Whitford in
his book, "The Metabolism and Toxicity of Fluoride" (Karger,1996),
"perfluorooctanoic acid (PFOA, octanoic acid fully saturated with 15
fluorine atoms)...(constitutes) about 20-30% of the nonionic fluoride in
This surface-active agent, which is a component of plasticizers,
lubricants, wetting agents, emulsifiers and other products, appear to enter
the body through contact with or ingestion of commercial products. It has
a very long half-life (approx. 1.5 years) in human males (Ubel et al., 1980)".
Thus the question raised by this new report in Nature is how many of the
byproducts from heating Teflon are accumulating insidiously in our bodies
like PFOA? Are any being passed onto the fetus? Will any of them turn out
to be endocrine disrupters?
Paul Connett, PhD, is a Professor of Chemistry at St. Lawrence
University, Canton, New York. He is also Director of the Fluoride Action
Network, an international coalition dedicated to ending water fluoridation
and alerting people to fluoride's health and environmental risks. Visit
their website at www.fluoridealert.org.
Follow-Up Comment from Dr C. Vyvyan Howard, MB, ChB, PhD,
It seems that it may be even worse than Paul Connett has portrayed.
When you heat Teflon (PTFE) up to the sort of temperatures that you get
in "state of the art" municipal waste incinerators (eg, 800°C)
you get the formation of CFCs, the major greenhouse gas that has been banned
as a refrigerant. When one considers the amount of clothing and fabric that
is coated with PTFE (most artificial fibres described as 'breathable') this
could have major implications for waste incineration.
Another aspect of heating PTFE in cooking utensils is the
following: A standard method of producing an aerosol of ultrafine particles
is to heat PTFE up to 480°C. This produces some gas-phase products,
mainly HF (hydrogen fluoride). If PTFE is further heated up to 500°C
other gas-phase products are produced, including perfluoroisobutylene and
others, which are highly toxic.
This is described in a paper by Obersdorster G, 'Toxicology
of ultrafine particles: in vivo studies'. Trans. Phil. R. Soc. Lond. A (2000)
358: 2719-2740. The rest of that issue of Trans Phil is dedicated to ultrafine
Ultrafine particles are defined as those below 0.1 microns
(100nm) and it is being demostrated that these have a toxicity all of their
own, which seems to be associated with their high chemical reactivity (that,
after all, is how we make heterogeneous catalysts!). I have recently edited
a book on this (Particulate Matter: properties and effects upon health.
Eds R L Maynard and C V Howard. Bios, Oxford (1999). ISBN 185996172X (Sorry
about the self advertising)).
However, it is appearing that the majority of the toxicity
of particulate aerosols may be attributable to the ultra-fine fraction.
This could have major implications for the use of Teflon (PTFE) coated cookware
in the home and industry. I am not aware that the tie up between the routine
use of these materials, ultrafine particle production and possible health
effects has yet been made.
Dr C. Vyvyan Howard, MB, ChB, PhD, FRCPath,
Developmental Toxico-Pathology Group,
University of Liverpool,
Liverpool L69 7ZA
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