Cornucopia Institute, a food and agriculture nonprofit found that most non-organic veggie burgers currently on the market are made with the chemical hexane, an EPA-registered air pollutant and neurotoxin. Cornucopia Institute senior researcher Charlotte Vallaeys, "If a non-organic product contains a soy protein isolate, soy protein concentrate, or texturized vegetable protein, you can be pretty sure it was made using soy beans that were made with hexane." The air pollutant is a byproduct of gas refining. In 2007, grain processors were responsible for two-thirds of our national hexane emissions. Workers who have been exposed to it have developed both skin and nervous system disorders. The FDA does not monitor or regulate hexane residue in foods. According to the report, "Nearly every major ingredient in conventional soy-based infant formula is hexane extracted."
The veggie burger list with hexane according to the report (pdf - page 37) is below along with hexane-free products:
Hexane: Amy's Kitchen, Boca Burger, conventional, Franklin Farms, Garden Burger, It’s All Good Lightlife, Morningstar Farms, President’s Choice, Taste Above, Trader Joe's, Yves Veggie Cuisine
Hexane-free products: Boca Burgers "Made with organic soy", Helen's Kitchen, Morningstar "Made with organic", Superburgers by Turtle Island, Tofurky, Wildwood