Your Teflon Frying Pan May Be Causing Problems
Nothing may stick to Teflon, but new research suggests that the by-products 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.
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 benign.
However, they had several problems:
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 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 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 foetus? 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, FRCPath:
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 particles.
Ultrafine particles are defined as those below 0.1 microns (100nm) and it is being demonstrated 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,
Teflon Chemicals are a Threat to Health
Dupont recently defended its position about partially complying with federal reporting guidelines on the health risks of a key ingredient found in Teflon.
The chemical giant has been criticized on many sides for its decision not to release all the information it compiled on perfluorooctanoic acid (PFOA), a soap-like ingredient used in making non-stick surfaces and materials. As a result, EPA has sought fines up to $300 million, arguing the company failed to inform the government and public about PFOA. The concerns:
The son of a DuPont factory worker who was born with only one nostril and other facial defects (he has had 30 operations) is one of eight families suing the company over PFOA. Although the man recently married, he and his spouse have opted not to have children in case they inherit his condition.
Two DuPont experts argued an internal document about elevated PFOA levels in childbearing workers and their infants wasn’t a toxicology report and didn’t meet the risk threshold that would’ve required contacting EPA. In fact, one attorney claimed PFOA and other chemicals were expected to pass through the placenta.
The company also believes EPA is unfair to apply DuPont’s internal guidelines to reporting requirements of higher PFOA levels in local drinking water when the government found three years ago levels could be raised 150 times without posing a health risk. However, a senior scientist at the Environmental Working Group pointed out that PFOA, like other fluoro-chemicals, is in people everywhere, never breaks down in the environment and is toxic at or near levels found in humans.
Another health issue, “Teflon flu” causes aches and pains when non-stick pans are overheated, although a DuPont spokesperson said the physical problems are temporary and pass quickly. Yet birds, particularly small ones like finches and cockatiels, can die in short order from those kitchen fumes.
A British environmental minister has said his country will eventually ban one chemical associated with PFOA, perfluorooctane sulphonate, along with other European countries and in line with the United States. One expert on perfluorinated polymers noted the PFOA in Teflon to be potentially as harmful as perfluorooctane sulphonate, pointing out that PFOA has been recognized as a rat carcinogen for decades.
Washington Post August 13, 2004
Telegraph August 8, 2004
Warning: Teflon Can Cause Birth Defects & Infertility
PFOA, a chemical found in products ranging from clothes to stain repellents to food packaging and cosmetics, and a component of Teflon production, poses developmental and reproductive risks to humans, according to a risk assessment form the U.S. Environmental Protection Agency (EPA).
Current PFOA exposures in children may be well above safe levels, and some children have high enough blood levels of PFOA to cause serious toxicity in laboratory studies.
The EPA reviewed PFOA after "unexpected toxicological and bioaccumulation discoveries" in the entire class of perfluorinated chemicals, particularly PFOS (perfluorooctane sulfonates), the active ingredient in Scotchgard, which was removed from the market by the EPA in 2000.
PFOS has similar chemical properties to PFOA. Neither product breaks down in the environment and both cause various cancers and adverse effects.
In animal studies PFOA has been associated with:
Other unrelated studies have also found evidence of birth defects in babies from PFOA-exposed workers. In 1981, two out of seven women who worked at a DuPont Teflon plant gave birth to babies with birth defects. DuPont then moved 50 women workers at the plant to reduce their exposure to PFOA.
Additionally, PFOA has been associated with tumours in at least four different organs in animal tests, and has been associated with increases in prostate cancer in PFOA plant workers.
The potentially harmful effects of PFOA are heightened because exposure is so widespread. Some 90 percent of the U.S. population has PFOA in their blood, some at levels as high as those found in PFOA factory workers.
According to the EPA, it is not known how humans are generally exposed to the substance. However, it has been suggested that PFOA’s longevity could be a contributing factor.
Unlike PCBs and DDT, PFOA does not break down in the environment, so it is infinitely persistent. Additionally, other classes of chemicals break down into PFOA, which means that even if PFOA were banned, levels of the substance in the environment could still increase due to the other chemicals.
In short, all of the PFOA generated by industries will remain in the environment indefinitely.
Although PFOA and related chemicals have been widely used in consumer products for 50 years, risks posed by such chemicals have only recently been exposed. Industry is not required to conduct safety tests on chemicals like PFOA in order to sell or use them. Due to this lack of regulatory authority, the EPA’s influence over chemical manufacturers is largely limited to requests for data once contamination creates a problem.
Environmental Working Group March 28, 2003
Comment: These new super-chemicals are going to make DDT look safe. It is absolutely amazing that companies can develop chemicals that essentially persist forever in our environment and not be held to a higher level of accountability to the chemicals’ effects on our health.
The take-home message is to stay as natural as possible, not only with your foods but also with your clothes and furniture. Natural fibers like cotton, which are free of spot-resistant treatments, certainly seem to be the wiser approach.
Additionally, store your food in glass, not plastic.