A New Safe and Efficient Home Insulation: Made from Soy

A reader writes The Green Guide:

We will be building a house soon, and wonder if you could tell us about safe insulation. Soybean foam and cellulose insulation is supposed to be "safe". How true is this? We would certainly appreciate some info from you on that matter. If soybean and cellulose are not safe, can you tell us about an alternative that is not cost prohibitive. Thank you for your help.
—G.C.

The Green Guide responds:

Green builders have no problem agreeing on the importance of good insulation in reducing energy waste. In fact, in a recent article on insulation, Environmental Building News plainly states that no matter the type of insulation used, if it is used appropriately, and installed efficiently, the environmental benefits will outweigh any negatives.

Both blown-in cellulose insulation, such as Redi-therm or Arctic, and soybean-based polyurethane foam, such as BioBase501 and Healthyseal, have gotten attention for their eco-sustainability.

When it comes to health concerns, blown-in cellulose has raised some debate about its safety for installers. Due to the high flammability of newspaper, cellulose insulation is treated with a fire retardant, either ammonium sulfate or a boron compound such as borax. According to an article in the British Journal of Industrial Medicine installers can inhale lethal toxic levels of boric acid. The article was quickly challenged by Energy Design Update for being written under the recommendation and funding of fiberglass manufactures, leading the author to recant, admitting that there was no definite evidence that harmful amounts of boric acid could be inhaled from exposure to cellulose. In any case, as with all insulation, cellulose should be installed with an airtight vapor barrier between itself and the living space. While fire-retardant levels in cellulose insulation could be toxic if ingested, as long as it isn't eaten it poses little threat to the homeowner or installers wearing proper respiratory protection.