http://www.healthsentinel.com/news.php?event=news_print_list_item&id=293
Tom Avril, "Chemical in Teflon, other goods is turning up in
disturbing places", Seattle Times, October 1, 2004,
Link: http://seattletimes.nwsource.com/html/health/2002050937_teflon01.html
More than 65 years ago in a south New Jersey laboratory, a DuPont
chemist accidentally invented a waxy, white powder that would become
one of the mainstays of the modern kitchen: Teflon.
Today, this nonstick marvel is getting attention far beyond the
stovetop.
A chemical used to make it, perfluorooctanoic acid — PFOA — has been
turning up in people and animals worldwide: river otters in Oregon,
polar bears in the Canadian Arctic and in the blood of 96 percent of
children tested in 23 states.
Scientists are not sure how the chemical is getting into people — not
from using Teflon pans, they say — and they don't know whether it
poses any danger at current levels.
But the substance does not break down in the environment. And it has
been linked to liver and developmental problems in lab rats, prompting
an unusually broad review by the Environmental Protection Agency.
"We need to get to the bottom of this," said Charles Auer, director of
the agency's Office of Pollution Prevention and Toxics.
PFOA is just one of dozens of synthetic intruders found in the human
body in recent years, thanks to increasingly sophisticated equipment
that allows scientists to measure the slightest traces of chemicals.
But this one has drawn unusual scrutiny.
DuPont agreed this month to pay at least $108 million to settle a
class-action suit brought by residents near a company plant in West
Virginia, where PFOA has been found in the drinking water.
And in July, the EPA — prompted partly by the research of a
Washington-based nonprofit called Environmental Working Group —
accused DuPont of failing to disclose certain health-related
information about PFOA from as early as 1981. A public hearing is
pending, after which an administrative-law judge can impose fines of
more than $300 million.
Meanwhile, a growing number of scientists, among them a team at the
University of Toronto, think the biggest source of PFOA is not Teflon
manufacture, but a related family of chemicals called telomers.
Telomers, made by DuPont and a few other companies, are widely used to
make grease- and stain-repellent coatings for take-out food boxes,
carpets and clothing.
Burger King, for example, stopped selling food in telomer-coated boxes
in 2002. McDonald's has said it uses such boxes, but would not say
whether it still does.
DuPont on defense
The various accusations have provoked consternation at DuPont, based
in Wilmington, Del., whose executives describe it as a "science
company" that cares about the environment.
The company says it has broken no laws and has sharply reduced
emissions of PFOA. And studies on plant workers have shown PFOA to be
safe, said Don Duncan, president of the Society of the Plastics
Industry, an industry group.
"It's not as if we've got people dropping in the streets out there,"
he said. In April 1938, Roy Plunkett was experimenting with
refrigerants in a DuPont lab in Deepwater, N.J., when something
strange happened.
His assistant opened a pressurized metal cylinder to release the gas
stored inside, but nothing came out.
The cylinder was too heavy to be empty. Intrigued, they turned it
upside down. A mysterious white powder fell out.
The gas molecules somehow had combined to form much longer polymer
chains, a new plastic that would turn out to be more slippery than
ice.
Company scientists eventually developed a way to repeat the accident
in mass quantities, with a process using another chemical, PFOA.
Eventually, Teflon and related substances were used to make pots and
pans, medical equipment, airplane parts and automobile fuel lines.
In 1968, 30 years after Plunkett's discovery, a University of
Rochester scientist noticed something odd.
Don Taves, a toxicologist, was testing human blood to see how much
fluorine was in it as a result of fluoridated water, which prevents
cavities.
The numbers were 10 times what he expected, recalled Taves, now 78.
After further research, he became convinced that synthetic
perfluorochemicals were at fault.
But Taves said he was not concerned about any health effects, and the
findings attracted little attention until 1997.
That year, 3M, the Minnesota chemical-maker that made PFOA and sold it
to DuPont, was measuring its workers' blood for a related chemical
that was produced during the manufacture of Scotchgard.
Company scientists obtained samples from nonworkers as a baseline to
compare the workers' blood. To their surprise, the chemical was
present in nonworkers, too.
In 2000, the company said it would voluntarily stop making the
chemical, perfluorooctane sulfonate, and find a new way to make
Scotchgard. At the same time, 3M said it would stop making a related
chemical that scientists had been finding in the environment: PFOA.
Faced with the loss of its key supplier, DuPont decided to start
making PFOA itself. Today, the DuPont plant in Fayetteville, N.C., is
the nation's lone manufacturer of PFOA.
Sitting in a freezer in a University of Pennsylvania laboratory,
hundreds of vials of blood may hold part of the answer to the big
question: Is PFOA a risk to human health?
A team led by Edward Emmett, a professor of occupational and
environmental medicine, is collecting the blood samples from people
who live near the DuPont plant in Parkersburg, W.Va., where the
lawsuit was settled.
With a government grant, the team will analyze the samples to see
whether there is a connection between PFOA and hormone levels and
liver function.
Though various industry studies have found no health effects from
PFOA, Emmett said some of the studies were small or not well-designed.
"We're at a pretty rudimentary stage in our knowledge," he said.
And past studies on lab animals have drawn an incomplete picture, in
part because their bodies do not handle the chemical in the same way.
For example, the half-life of PFOA in humans is believed to be about
four years, meaning it takes that long for people to flush half of the
chemical out of their systems. Rats get rid of the chemical in days.
In a preliminary assessment last year of risks to human development,
the EPA found the chemical levels linked to problems in rats to be
from less than 70 to more than 9,000 times the levels found in women
and children.
For some subtle health effects, including a weaker immune system and
low organ weights, scientists have found no dose of the chemical that
is totally safe in rats.
Rather than wait for more studies, critics advocate a precautionary
approach: Stop making the suspect chemicals.
"We're already to the point where it is in people and getting near the
point where there's significant risk," said Tim Kropp, a toxicologist
at Environmental Working Group.
Possible sources
Meanwhile, industry, university and government scientists are hard at
work trying to solve the other mystery: How do PFOA and other
perfluorochemicals get into people to begin with?
Could it be from the water? The air? Dust from vacuuming
stain-resistant carpets? Suddenly, it's a hot research topic.
In the past three years, journals publishing papers on
perfluorochemicals have grown tenfold, to nearly 50, according to the
journal Environmental Science & Technology.
"Scientists are way behind," said Keri Hornbuckle, a University of
Iowa engineering professor. "We're scurrying to figure out all the
chemical pathways that these chemicals go through."
One possibility: When people wash their stain- or water-resistant
clothes, the chemical coatings may go down the drain and into the
environment.
Another theory is that some residues escape into the air, where they
break down into PFOA or similar substances — some of them thought to
pose even greater risk.
Hazards discounted
In a study awaiting publication, DuPont scientists say they find no
risk associated with the everyday use of coated clothing, carpets and
cookware, among other products. PFOA is not present in these final
products except sometimes in trace amounts.
"We can say unequivocally that those articles are safe," said Robert
C. Buck, a Ph.D. chemist and senior research scientist for the
company.
The FDA, which has approved 30 perfluorochemicals for food packaging
and processing since 1958, says there is no sign of a direct risk from
food.
But exposure from package disposal or deterioration must still be
ruled out, said George Pauli, a senior official at the FDA's Office of
Food Additive Safety.
The perfluorochemicals are heralded for their durability and nonstick
qualities, but some of them may be sticking around too long.
