"We are confident when we say that the facts, the scientific facts, demonstrate that the material is perfectly safe to use," Uma Chowdhry, Dupont's vice president of research and development, told "20/20." Chowdhry is the DuPont executive chosen to defend Teflon, and she claims that the substance is completely safe, despite the fact that the key chemical, C-8, is in everyone's blood.
"We do not believe there are any adverse health effects," she said. "There are lots of chemicals that are present in our blood."
Now the unexpected discovery of the almost universal contamination of Americans' blood from C-8, combined with worrisome laboratory studies, has led to a high priority investigation by the EPA of the chemical's risks.
"It's a potential threat," said Houlihan. "And the EPA's moving fast in studying this. Human blood levels are too close to the levels that harm lab animals. That's why they're moving too fast."
There is another more immediate health problem from Teflon, according to the Environmental Working Group. Cooking with Teflon can make a person sick with a temporary flu if a nonstick pan gets overheated.
"It feels like the flu," said Houlihan, "headaches, chills, backache, temperature between 100 and 104 degrees."
DuPont says that fumes are released from the pan when it is overheated, which it says occurs at temperatures that are not reached during normal cooking.
As the Environmental Working Group showed "20/20" in a kitchen demonstration, however, a pan can reach that temperature in just a few minutes.
"At 554 degrees Fahrenheit," said Houlihan, "studies show ultrafine particles start coming off the pan. These are tiny little particles that can embed deeply into the lungs."
The hotter the pan gets, the more chemicals are released. "At 680, toxic gases can begin to come off of heated Teflon," Houlihan said.
It turns out, DuPont has known about the "Teflon flu" for years.
"You get some fumes, yes," said Chowdhry, "and you get a flu-like symptom, which is reversible." Chowdhry said the flu is temporary and lasts at most for a couple of days. She also added that a warning about the flu, while not on the pans themselves, is on the DuPont Web site.
In the demonstration for "20/20," a piece of bacon was just getting crisp when the Teflon pan went beyond the initial warning point of 500 degrees.
"I've never cooked bacon," said Chowdhry. "I can't comment."
The Environmental Working Group has tried without success to get the government to order that warning labels be put on nonstick pans.
One consumer warning DuPont does issue about Teflon fumes involves not humans, but birds. The fumes from overheated Teflon pans can be lethal to them.
Shelby Greenman told "20/20" that her pet cockatoo keeled over in its cage down the hall from the kitchen after all the water boiled out of a Teflon pan.
"I didn't smell anything, I didn't see any smoke," she said. "As soon as they inhale it, it's over. There's nothing they can do to help them."
Bird owner groups say thousands of birds have been killed by Teflon fumes. DuPont says this occurs because birds have small and sensitive lungs.
"People should not have birds in an unventilated kitchen," said Chowdhry.