Cellulose insulation treated with Boron No. 10 restricts the growth of common indoor molds, according to a five-month study conducted at Truman State University in Kirksville, Mo.

In the initial phase of the study, which was conducted in 2004 by Dr. Jose Herrera, four different brands of Boron No. 10-infused cellulose insulation were tested for their anti-fungal properties. Samples of Nu-Wool from Wallseal, FIBER-LITE from Fiberlite Technologies, Thermolok by Hamilton Manufacturing and InCide Pest Control Insulation from InCide Technologies were sprayed into wall cavities and then inoculated with an artificially high concentration of common household molds. The insulation was monitored for mold growth for 124 days.

Because the Boron No. 10-treated cellulose samples so effectively controlled fungal growth, the research team zeroed in on an untreated sample, which had been inoculated with the same super-moldy mixture. “The untreated samples were much more likely to harbor fungi,” states Herrera. The control sample “harbored multiple species, which remained high and even increased” during the course of the study. This led him to conclude sodium polyborate (Boron No. 10) has a natural elimination effect on microscopic environmental invaders and is “likely to inhibit growth of most (if not all) species of mold.”