Steel is used is all sorts of cookware, from pots and pans to baking sheets and utensils. Stainless steel is used for its cleanliness and resistance to rust. However, stainless steel involves an alloy with chromium in the mix. While the chromium protects the steel from rusting, it also makes direct contact with food on the metal surface.
The amount of chromium transferred to cooked food in each dish is so small, no noticeable health effects tend to occur. However, chromium exposure over time has been known to be carcinogenic -- that is, a cause of cancer -- and chromium can also trigger allergies and skin reactions in great doses. This is not the typical exposure level seen, however, in cooked food exposed to a stainless steel pan.
Effects from Cooking
Chromium is the most likely exposure from stainless steel cookware. However, that exposure has yet to be conclusively linked with specific health risks as a result of prolonged use of stainless steel pots and pans. Unlike aluminum cookware, which has raised questions with regards to potential links to Alzheimer's Disease, stainless steel cookware has had no such alerts to date.
If you are concerned about using stainless steel pans, experts recommend you line the pans with oil regularly before cooking. Not only does this avoid burning, it reduces direct contact with the food. Acidic foods are the most worrisome; cooking is fine but don't leave the food in the steel pan for longer than necessary when finished.