Perfluorooctanoic acid (PFOA), is a synthetic compound found in non-stick pans, as well as grease-resistant food packaging and paper products, such as microwave popcorn bags and pizza boxes.  

PFOA is a toxicant and carcinogen in animals, persistent in the environment, and detected in the blood of general populations in the low parts per billion range where it has been linked to infertility. In people with higher exposures, PFOA is linked to birth defects, increased cancer rates, and changes to lipid levels, the immune system, and liver, effects identified in animals.

References

Emmett EA, Shofer FS, Zhang H, Freeman D, Desai C, Shaw LM (August 2006). "Community exposure to perfluorooctanoate: relationships between serum concentrations and exposure sources". J Occup Environ Med. 48 (8): 759–70. doi:10.1097/01.jom.0000232486.07658.74. PMID 16902368.