This is...disturbing.

What is hexane?

A study found hexane in soy protein. Should you stop eating veggie burgers? - By Brian Palmer - Slate Magazine:

"The FDA does not currently impose a ceiling on hexane residue in soy foods, but it does limit how much of the chemical can be left in fish protein isolate (5 parts per million), as well as in hop extract and spice resins (25 ppm). The study (PDF) that's now in the news found 21 ppm of hexane in soy meal—the defatted soy flakes that are used in products like energy bars and veggie burgers. The authors of the study told the Explainer that more recent testing has found concentrations as high as 50 ppm. But that's no reason to throw your meatless breakfast links down the disposal. The hexane limits are precautionary. No study has ever tested how much hexane a person can safely eat over the course of a lifetime, but rodent studies suggest that your Thanksgiving tofurkey isn't going to kill you."