Sandra Cummins was furious when she walked out of her Lufkin, Texas home one day five years ago and found her husband coating her Chevy with what looked like shaving cream. But the crews fighting forest fires in Texas and the Carolinas this spring can testify that what Mark Cummins was doing was more practical than joke. The "shaving cream" was actually a cheap and efficient fire-fighting foam that Cummins, 36, was developing. Nicknamed "Texas Snow Job," it now is carried by 150 Texas Forest Service vehicles and is in experimental use elsewhere.

Foam has been used to fight blazes for 100 years and is especially effective in forests, expanding the often-limited water supply tenfold. But the process is expensive: The necessary chemicals sell for up to $23 per gallon and the trucks generating the foam through multichambered systems usually cost $100,000 plus.

In 1975, however, while charging a conventional foam system with gas, an observant Cummins noticed that a mixture of air and pressure produced foam without circulating through any chambers. He began to develop his stripped-down system. A pickup fitted with his invention, which utilizes a 250-gallon tank for the water and chemicals and an air compressor, costs a mere $10,000, including the price of the truck. Cummins also has found a cheap substitute for the chemicals—"pine soap," a nontoxic by-product of papermaking that runs just 30 cents a gallon. The soap smells faintly like Baretta's socks, Cummins observes, "but that's better than burnt meat." He's got a point. Texas Snow Job has already saved equipment, and Cummins' chief, Pat Ebarb, predicts it will save lives. When men are suddenly overrun by flames while bulldozing firebreaks, they can cover themselves in a cocoon of the foam and the fire should rage past them, leaving them unscathed.

Cummins' fascination with fire gear comes naturally—his father once sold it in Fort Worth. But age-old methods still abound, with forest services even now relying on plows, buckets and shovels. Mark Cummins hopes to improve on that. Not content with his Snow Job, he's now back at his drawing board. His dream: to develop fire-zapping laser beams.