Soy Burger With a Side of Toxin?

Vegetarian burger lovers, take note. Your tasty patty may come with an unwanted condiment: Hexane.

Many popular brands of soy-based vegetarian foods, such as Morningstar Farms, Trader Joes, Amy's Kitchen, Boca Burger, Yves and others, may include a decidedly un-green petroleum byproduct of gasoline refining, Mother Jones magazine reports.

In an effort to produce lower fat products for health conscious consumers, soy-based faux meat manufacturers use hexane, an EPA-labeled air pollutant and neurotoxin, to separate the oil from the protein, according to a report by the Wisconsin-based agricultural non-profit the Cornucopia Institute.

"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," Cornucopia Institute senior researcher Charlotte Vallaeys told Mother Jones.

The FDA does not set a maximum residue level in soy foods for hexane, and does not require that food manufacturers test for hexane residues, according to the report.

The effects of consuming foods that contain hexane-extracted ingredients are not known. However, chronic and long-term and exposure to hexane in the air (such as in factories producing certain glues and solvents) is associated with numbness in the extremities, muscular weakness, blurred vision, headache, and fatigue observed, according to the EPA.

Not all soy products contain hexane, however. Helen's Kitchen, Tofurky, Turtle Island and Wildwood are among the brands that do not use hexane. Morningstar Farms and Boca Burgers have hexane-free products as well. Look for the label that says "made with organic soy."