July 19, 2001.

Dear All,

An article in the latest issue of Nature ( July 19, 2001) highlights the dangers posed by heating teflon. 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 which 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 benign. However, they had several problems: a) they tended to be very persistent in the environment b) they are fat soluble and resistent to normal detoxification processes in the liver c) they accumulate and concentrate in animal and human body fat, d) they get passed on by the mother to the fetus through the placental membrane and then to the infant via breastmilk, e) 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) AND f) 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). 12 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. An interesting aside is that the fluoride ion is not just persistent it is permanent. 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 stratetgy 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 human plasma. 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 commerical 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?

Thanks to Cory Mermer for forwarding us this summary of the article in Nature.

Paul Connett.

Subject: New study in "Nature" regarding Teflon and Fluoride release Date: Thu, 19 Jul 2001 11:36:58 -0400

Heat attacks teflon

When heated, teflon frying pans release substances containing fluorine, which can only be broken down very slowly in the environment. This is being reported by Canadian scientists in today's issue of "Nature". The researchers state that some of these substances accumulate in the ground and in groundwater.

Other substances, on the other hand, may cause a breakdown of ozone in the upper atmosphere layers.

Teflon is part of a group of polymers containing flourine. Apart from frying pans and ovens, these polymers are also in used in internal combustion engines and in the medical field.

When the researchers heated these polymers, they released a veritable cocktail of chemical fragments. Some of these fragments are already known to contribute to the destruction of the ozone layer in the stratosphere and to the green house effect.

Another chemical fragment found was triflouride acetic acid. This substance has often been detected in rainwater, but its origin has been unclear. This substance is very slow to break down, and very little research has been done on its long term effects on the environment.

Source: Nature, 18.07.01

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, Kanada; in Nature, Vol. 412, No. 6844, July 19. 2001, pp 312- 324