Eat your hexane, children.

The Cornucopia Institute published a study that examined the use of Hexane in processing foods, noting that the FDA has set no maximum levels for residual Hexane in soy foods with one exception: Hexane is not allowed in foods labeled organic. Be careful though; products listed as, "Made with organic ingredients" aren't certified organic and do not have the same requirements to keep Hexane out of their products; Clif Bar is one such product that falls into this category.

So what's Hexane? It's a byproduct of petroleum which:

Is used to extract edible oils from seeds and vegetables, as a special-use solvent, and as a cleaning agent.
Acute (short-term) inhalation exposure of humans to high levels of hexane causes mild central nervous system (CNS) effects, including dizziness, giddiness, slight nausea, and headache. Chronic (long-term) exposure to hexane in air is associated with polyneuropathy in humans, with numbness in the extremities, muscular weakness, blurred vision, headache, and fatigue observed.
Neurotoxic effects have also been exhibited in rats.
(Excerpt from EPA's summary of Hexane)

Now, for the scary list. Soy burgers that use hexane-processed soy:

• Amy’s Kitchen
  
• Boca Burger, conventional
  
• Franklin Farms
  
• Garden Burger
  
• It’s All Good
  
• Lightlife
  
• Morningstar Farms
  
• President’s Choice
  
• Soy Boy
  
• Taste Above
  
• Trader Joe’s
  
• Yves Veggie Cuisine
  

And of course, the good list. Soy burgers with no hexane-processed soy:

• Boca Burgers “Made with organic soy”
  
• Helen’s Kitchen
  
• Morningstar “Made with organic”
  
• Superburgers by Turtle Island
  
• Tofurky
  
• Wildwood
  

(From Cornucopia Institute's study, "Behind the Bean" - link to pdf)

Oh, and this isn't just an issue with soy burgers. Soy milk that isn't labeled "Organic" and any other foods that don't specify that it is "Organic" uses soy that is processed with hexane. Again, those foods processed with hexane have no rules governing maximum levels of residual hexane. Scary.

-via BoingBoing, via Mother Jones