What are Teflon
and PFOA? Where are they found?
Teflon® is a brand name for a man-made
chemical known as polytetrafluoroethylene (PTFE). It has been in commercial use
since the 1940s. It has a wide variety of uses because it is extremely stable
(it doesn’t react with other chemicals) and can provide an almost frictionless
surface. Most people are familiar with it as a non-stick coating surface for
pans and other cookware. It is also used in many other products, such as fabric
protectors.
Perfluorooctanoic acid (PFOA), also
known as C8, is another man-made chemical. It is used in the process of making
Teflon and similar chemicals (known as fluorotelomers), although it is burned
off during the process and is not present in significant amounts in the final
products.
PFOA has the potential to be a health
concern because it can stay in the environment and in the human body for long
periods of time. Studies have found that it is present worldwide at very low
levels in just about everyone’s blood. Higher blood levels have been found in
community residents where local water supplies have been contaminated by PFOA.
People exposed to PFOA in the workplace can have levels many times higher.
PFOA and some similar compounds can be
found at low levels in some foods, drinking water, and in household dust.
Although PFOA levels in drinking water are usually low, they can be higher in
certain areas, such as near chemical plants that use PFOA.
People can also be exposed to PFOA from
ski wax or from fabrics and carpeting that have been treated to be stain
resistant. Non-stick cookware is not a significant source of PFOA exposure.
Do Teflon and
PFOA cause cancer?
Teflon
Teflon itself is not suspected of
causing cancer.
PFOA
Many studies in recent years have looked
at the possibility of PFOA causing cancer. Researchers use 2 main types of
studies to try to figure out if such a substance might cause cancer.
Studies in the lab
In studies done in the lab, animals are
exposed to a substance (often in very large doses) to see if it causes tumors
or other health problems. Researchers might also expose human cells in a lab
dish to the substance to see if it causes the types of changes that are seen in
cancer cells.
Studies in lab animals have found
exposure to PFOA increases the risk of certain tumors of the liver, testicles,
mammary glands (breasts), and pancreas in these animals. In general,
well-conducted studies in animals do a good job of predicting which exposures
cause cancer in people. But it isn’t clear if the way this chemical affects
cancer risk in animals would be the same in humans.
Studies in humans
Some types of studies look at cancer
rates in different groups of people. These studies might compare the cancer
rate in a group exposed to a substance to the cancer rate in a group not
exposed to it, or compare it to the cancer rate in the general population. But
sometimes it can be hard to know what the results of these types of studies
mean, because many other factors might affect the results.
Studies have looked at people exposed to
PFOA from living near or working in chemical plants. Some of these studies have
suggested an increased risk of testicular cancer with increased PFOA
exposure. Studies have also suggested possible links to kidney cancer and thyroid
cancer, but the increases in risk have been small and could have been due to
chance.
Other studies have suggested possible
links to other cancers, including prostate, bladder,
and ovarian cancer.
But not all studies have found such links, and more research is needed to
clarify these findings.
What expert
agencies say
Several national and international
agencies study different substances in the environment to determine if they can
cause cancer. (A substance that causes cancer or helps cancer grow is called
a carcinogen.) The American Cancer Society looks to these
organizations to evaluate the risks based on evidence from laboratory, animal,
and human research studies.
The International Agency for
Research on Cancer (IARC) is part of the World Health Organization
(WHO). One of its goals is to identify causes of cancer. IARC has classified
PFOA as “possibly carcinogenic to humans” (Group 2B), based on limited evidence
in humans that it can cause testicular and kidney cancer, and limited evidence
in lab animals.
(For more information on the
classification system IARC uses, see Known and
Probable Human Carcinogens.)
The US Environmental Protection
Agency (EPA) maintains the Integrated Risk Information System (IRIS),
an electronic database that contains information on human health effects from
exposure to various substances in the environment. The EPA has not officially
classified PFOA as to its carcinogenicity.
In a draft (not final) report, the EPA’s
Scientific Advisory Board examined the evidence on PFOA, mainly from studies in
lab animals, and stated that there is “suggestive evidence of carcinogenicity,
but not sufficient to assess human carcinogenic potential.” The board agreed
that new evidence would be considered as it becomes available.
Other agencies have not yet formally
evaluated whether PFOA can cause cancer.
What is being
done about PFOA?
The long-term effects of PFOA and
similar chemicals are largely unknown, but there has been enough concern to
prompt an attempt to phase out industrial emissions of them. Only a handful of
companies have used these chemicals in manufacturing in recent years.
While the possible long-term health
effects of PFOA are not known, the issue is currently under study by the EPA
and other agencies. In addition, in 2006, the EPA and the 8 manufacturers who
used PFOA at the time agreed to a “stewardship program.” The goals were for the
companies to reduce factory emissions and product content levels of PFOA by 95%
by the year 2010, and to eliminate PFOA from emissions and product contents by
the end of 2015. The companies have submitted annual reports on their progress
to the EPA, and the latest reports indicated a large reduction in use of these
chemicals. The decreasing demand for PFOA has also led to many companies
phasing out production.
The EPA does not regulate the levels of
PFOA or related chemicals (such as perfluorooctane sulfonate, or PFOS) in
drinking water at this time. However, in 2009, the EPA released provisional
health advisories (PHAs) for PFOA and PFOS in drinking water. These advisories
recommend that actions should be taken to reduce exposure when contaminants go
above a certain level in the drinking water – 0.4 µg/L (micrograms per liter)
for PFOA and 0.2 µg/L for PFOS. These advisories are not legally enforceable
federal standards and are subject to change as new information becomes
available.
Should I take
measures to protect myself, such as not using my Teflon-coated pans?
Other than the possible risk of flu-like
symptoms from breathing in fumes from an overheated Teflon-coated pan, there
are no known risks to humans from using Teflon-coated cookware. While PFOA is
used in making Teflon, it is not present (or is present in extremely small
amounts) in Teflon-coated products.
Because the routes by which people may
be exposed to PFOA are not known, it is unclear what steps people might take to
reduce their exposure. According to the US Centers for Disease Control and
Prevention (CDC), people whose regular source of drinking water is found to
have higher than normal levels of PFOA or similar chemicals might consider
using bottled water or installing activated carbon water filters.
For people who are
concerned they might have been exposed to high levels of PFOA, blood levels can
be measured, but this is not a routine test that can be done in a doctor’s
office. Even if the test is done, it’s not clear what the results might mean in
terms of possible health effects.Tags:teflon,teflon ptfe,PFOA
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