Certain environmental agents have been linked to the development of certain paranasal sinus malignancies. Squamous Cell Carcinoma (SCC) has been associated with things like aflatoxin, which is produced by Aspergillus fungi that can colonize and contaminate grain; chromium, nickel, hydrocarbons and other organic chemicals. Adenocarcinoma has been linked with wood dust exposure. Both these malignancies are also linked with exposure to tobacco smoke, salted and smoked foods and heavy metals. Although inverted papillomas are benign, there is a risk of malignant transformation to SCC.