HOT SPRINGS, S.D. - It was the most intense fire ever recorded in the Black Hills National Forest, but nearly all homes coated with a slimy gel were saved while dozens of houses nearby burned to the ground.

The gel was a super-absorbent polymer that can hold many times its weight in water and clings well to vertical surfaces and glass. It is mixed with water and then can be sprayed on homes with a truck-mounted hose or a backpack apparatus, or dropped from a plane.

The substance is relatively new to firefighting, having been developed about a decade ago, and is not widely used. But some firefighters who have tried it are impressed, saying it offers longer-lasting protection than the foam retardants that have been around for many years.

"This stuff really works," Ed Waggoner of Reno, Nev., a retired California fire boss who now helps direct attacks on large forest fires in the Black Hills. "We're talking about a water bubble that you put on your house two or three hours before the fire gets there, and it'll save it when the fire gets there."

Firefighter Gorden Sabo applied fireproof gel to 20 homes in August near Sheridan during the Little Goose Fire that swept across 7.5 square miles of forest. Three homes were destroyed and about 100 others were threatened in that blaze. Sabo gelled 20 homes, including three that were in the direct path of the fire and could not be saved.