Captafol: A fungicide used by farmers outside of the U.S. that has been shown to induce cancer in experimental animal studies, captafol has been banned in the U.S. since 1999.
Certain glass and wool fibers (inhalable): These are commonly found in home insulation products. Some of these low-cost, general-purpose fibers are typically used for insulation and premium special-purpose wool and fibers used for thermal and sound insulation.
Cobalt-tungsten carbide (in powder and hard metal form): Used in hard metal manufacturing.
Ortho-Nitrotoluene: Used in synthetic dyes such as magenta and various sulfur dyes for cotton, wool, silk, leather and paper. In addition, it is used as an intermediate in the synthesis of explosives and a variety of organic chemicals, including compounds used in agricultural chemicals, pesticides, petrochemicals, pharmaceuticals and rubber industries.
Riddelliine: Contained in some plants, they are not used for food in the United States and have no known commercial uses.
ABC News' Lara Salahi contributed to this article.