Still, in 2016 Skittles publicly declared it would get rid of the chemical compound in its products, according to a press release at the time from the Center for Food Safety, which called the substance harmful and potentially poisonous. But the ingredient remains, according to the lawsuit, which alleges the candy company is misleading consumers by not having eliminated titanium dioxide.

The FDA's Code of Federal Regulations allows for the legal, regulated use of titanium dioxide in food products, under some restrictions.

Lithopone, a white pigment composed of a mixture of barium sulfate and zinc sulfide, is commonly used in the leather industry as a coloring agent. Leather suppliers around the world rely on lithopone to achieve the desired color and finish on their products.