By Cara Lynn Shultz

Cases of "Teflon flu" — an ailment associated with cooking in a nonstick pan — are rising, leading to questions about just how safe the nonstick cookware is to use.

Teflon is the brand name for polytetrafluoroethylene (PTFE), and is "among the most chemically inert, nontoxic, and nonflammable substances tested under normal usage conditions, and is not metabolized,” a report in Earth and Planetary Sciences said.

The problem arises “if a pan is left on a burner too long and the pan overheats or goes dry,” the National Capital Poison Control Center says.

That’s when you could be at risk of what's commonly known as "Teflon flu" — or its technical term, “Polymer fume fever.”

As the National Library of Medicine explains, it’s “an underrecognized flu-like illness associated with inhaling the thermal degradation byproducts of fluorocarbons. Overheating polytetrafluoroethylene (PTFE) coated nonstick (Teflon®) cookware represents the most common avenue of exposure.”

“Patients with polymer fume fever classically present with fever, malaise, dyspnea [shortness of breath], chest tightness, and a dry cough a few hours after exposure.”

Significant exposure can lead to pulmonary edema (potentially life-threatening lung congestion) or leukocytosis (a high white blood cell count) in humans; If you have pet birds, however, the Poison Control Center cautions that “even normal amounts of heat can produce enough toxic fumes to cause illness in birds. Unfortunately, the first sign of this illness in birds is often sudden death.”

As for humans, cases of “Teflon flu” are on the rise, with suspected 267 cases of the illness reported last year — the most since 2000.

Some experts think the illness is still underreported: “If you have a fever and you have body aches, you don’t always think that it’s something that you inhaled,” Maryann Amirshahi, the co-medical director for the National Capital Poison Center in Washington, told the outlet.

However, there are ways to avoid the illness: “It’s always good practice to use a vent hood system due to the smoke point of food and the chemicals used to cook the food,” said Sisavath Keovilay, PhD, chef and baking and pastry university department chair at Keiser University Center for the Culinary Arts.

And you should never heat your nonstick pan without something in it.

“Even if you just start with the butter or oil that you plan to cook your food in, that should be enough to reduce the chances of the coating breaking down,” said Shawn Matijevich, lead chef-instructor of online culinary arts and food operations at the Institute of Culinary Education.

Some experts, meanwhile, suggest simply skipping non-stick.

“If you're concerned about using Teflon pans, I would recommend investing in a good cast iron pan,” said Keovilay.

“When a cast iron pan is well seasoned, nothing will stick to it."