A preventive treatment was developed that uses an environmentally benign gel-like fluid to help common wildland fire retardants last longer on vegetation. Applied to ignition-prone areas, the materials retain their ability to prevent fires throughout the peak fire season, even after weathering that would sweep away conventional fire retardants. By stopping fires from starting, such treatments can be more effective and less expensive than current firefighting methods.

The most widely deployed commercial wildland fire-retardant formulations use ammonium phosphate or its derivatives as the active fire-retarding component; however, these formulations only hold retardants on vegetation for short periods of time, so they can’t be used preventively. The new cellulose-based gel-like fluid stays on target vegetation through wind, rain, and other environmental exposure.

The retardant materials were tested on grass and chamise — two vegetation types where fire frequently starts. The treatment was found to provide complete fire protection even after half an inch of rainfall. Under the same conditions, a typical commercial retardant formulation provides little or no fire protection.

The treatment contains only nontoxic starting materials widely used in food, drug, cosmetic, and agricultural products. The unique properties of these gel-like retardant fluids allow them to be applied using standard agricultural spraying equipment or from aircraft. While it washes away slowly, providing the ability to protect treated areas against fire for months, the materials eventually degrade.

For more information, contact Eric Appel, School of Engineering, at This email address is being protected from spambots. You need JavaScript enabled to view it.; 562-320-8779.