The Corrosive Reality of Oil Extraction

We all love our plant oils and extracts- but have you ever stopped to think about just how they take the oil out of these plants? Most oils from plant sources are extracted through a process involving either, a mechanical press or chemical solvent (or a combination of the two). Historically, extraction was performed mechanically- with relatively low production yields and a large amount of waste. Way back during the Industrial Revolution, technology took hold and the widespread use of the continuous mechanical press allowed for a more efficient extraction system. It was in the 1930s that solvent extraction became popular when it was recognized for its effectiveness in recovering oil from seeds and other oil-bearing materials. Currently, hexane is the most widely used extraction solvent. The problem is that hexane’s toxicity is well established; it is an extremely corrosive, neurotoxin, not to mention air pollutant, with strict OSHA regulations regarding its use and worker safety practices. A petroleum by-product of gasoline refining, hexane is highly volatile and is assumed to completely evaporate from food oils; the FDA does not set maximum residue limits for hexane extracted products, except for cottonseed oil and hops. To add injury to insult: the EPA lists hexane as a hazardous air pollutant; air pollutants are defined by the EPA as airborne chemicals that “cause or may cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental and ecological effects.”¹ The consensus regarding lab studies testing for residual hexane in food oils is that it is generally undetectable, and therefore extraction with hexane is deemed safe. The Cornucopia Institute recently tested various soy products for the presence of hexane. The Institute sent various foods containing soy lecithin to an independent lab, which found hexane residues ten times greater than what is considered acceptable by the EPA. EPA reports up to 0.2 percent of hexane by volume of oil can be present in oil after extraction.

We all love our plant oils and extracts- but have you ever stopped to think about just how they take the oil out of these plants?

Most oils from plant sources are extracted through a process involving either, a mechanical press or chemical solvent (or a combination of the two).  Historically, extraction was performed mechanically- with relatively low production yields and a large amount of waste.  Way back during the Industrial Revolution, technology took hold and the widespread use of the continuous mechanical press allowed for a more efficient extraction system.

It was in the 1930s that solvent extraction became popular when it was recognized for its effectiveness in recovering oil from seeds and other oil-bearing materials.  Currently, hexane is the most widely used extraction solvent.  The problem is that hexane’s toxicity is well established; it is an extremely corrosive, neurotoxin, not to mention air pollutant, with strict OSHA regulations regarding its use and worker safety practices.  A petroleum by-product of gasoline refining, hexane is highly volatile and is assumed to completely evaporate from food oils; the FDA does not set maximum residue limits for hexane extracted products, except for cottonseed oil and hops.  To add injury to insult: the EPA lists hexane as a hazardous air pollutant; air pollutants are defined by the EPA as airborne chemicals that “cause or may cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental and ecological effects.”¹

The consensus regarding lab studies testing for residual hexane in food oils is that it is generally undetectable, and therefore extraction with hexane is deemed safe. The Cornucopia Institute recently tested various soy products for the presence of hexane. The Institute sent various foods containing soy lecithin to an independent lab, which found hexane residues ten times greater than what is considered acceptable by the EPA.  EPA reports up to 0.2 percent of hexane by volume of oil can be present in oil after extraction.

Soy lecithin’s use is virtually ubiquitous in food manufacturing as it acts as an emulsifier and prolongs shelf life.  It can be found in foods such as, but not limited to, chocolate, coffee creamer, infant formula and peanut butter.  Another unsettling fact is that choosing “organic” may not exempt you from consuming hexane extracted ingredients; unless a food is certified USDA organic (95% or above) you can not be 100% sure. Products like soy lecithin were historically unavailable in organic form.  Organic soy lecithin (made without using hexane or other harsh environmentally unfriendly chemicals) is now available, but recent updates in USDA’s organic standards have failed to include organic soy lecithin as a requirement.  This can be thought of as a convenience and cost cutter for food manufactures, as organic soy lecithin is 8 times more expensive than its hexane bathed counterpart.

Solae, a major supplier of soy protein ingredients found in vegetarian burgers, energy bars, and other ‘all-natural’ foods, emitted (polluted) nearly one million pounds of hexane from its Ohio and Illinois factories. As the seventh largest emitter of hexane in the US, Solae’s plant in Bellevue, Ohio, released more hazardous hexane than other major sources including Exxon Mobil’s oil refinery plant in Baytow, and Firestone’s tire factory in Orange, Texas.


¹ http://www.epa.gov/ttn/atw/allabout.html