Gorden Sabo applies fire-retardant gel to a home on Aug. 12 near Sheridan, Wyo., during the Little Goose Fire that swept across 7.5 square miles of forest. Three homes were destroyed and about 100 others were threatened. The home sprayed by Sabo was saved.

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.”

Kim Zagaris, fire chief in the California Office of Emergency Services, said all 122 of the fire trucks under his command carry gel. And county officials in San Diego recently gave the Palomar Mountain volunteer fire department a grant to buy gel that residents can spray on their homes.

In the last decade, thousands of homes – mostly in Rocky Mountain and Western states – have been destroyed by wildfires. Many were ignited by embers that rained down on them well ahead of the flames.

Foam stands up to the heat from fire for only 15 minutes or so, while gel can protect for several hours, and can withstand direct flames, according to firefighters. And the gel – a few hundred dollars’ worth can save a home – can be replenished with water merely by misting it every few hours. It is biodegradable and can be washed off with a hose or a pressure sprayer.

Some firefighters say gel is not more widely used because it is still new, the firefighting industry can be slow to embrace new technology, and the backpack sprayers can be slow and unreliable at higher altitudes.