FORT LAUDERDALE, Fla. (AP) _ The normal view is smoky nothingness, a fumbling disorientation shared by victims and firefighters in burning buildings.

But a new helmet that uses thermal-imaging technology borrowed from the military gives firefighters a clear image contrasting hot as white and cold as black. For the first time, they can see through smoke.

``Firefighting has changed very little in 150 years: put the wet stuff on the red stuff,'' said city fire Division Chief Steve McInerny, whose department bought six helmets. ``It's almost so futuristic it's hard to compare the ability we have with it.''

The 10.6-pound device that mounts on a standard fire helmet is designed to help save lives, reduce property damage and make work safer for firefighters, who often enter weakened buildings, fall into holes in floors and crawl into trouble.

The CairnsIRIS helmet combines heat-sensing gear and an electronic display. A heat sensor on the side of the helmet feeds data to a waistband power pack and up to the viewer, whose eyes are blocked by the odd-shaped display.

But looking into the flip-down binocular lenses, the wearer can see anything that varies from air temperature. People give off a white glow, and their footprints are visible for several seconds because of the body heat left behind. Cold water looks like gray lava, a 2-inch flame on a gas stove looks 2 feet tall as its heat rises. Chilly air spreads out like dirt from a ceiling vent.

The helmet even lets the user see through the side of a propane tank to gauge the level of liquid gas inside because it's cooler than the metal.

After weeks of training, Fort Lauderdale firefighters took the helmets out for the first time in December and ended up using them three times that day: in a fire at the home of a family of 13, an auto body shop where workers smelled smoke and a shed fire threatening to spread to a garage where antique trucks were parked.

At the house, firefighters were blinded by the smoke. The helmet wearer entered as tongues of flame advanced from the back to the front. The quick determination? No one was at home.

At the auto shop, a ballast on a fluorescent light broken for a couple of years was too hot to be touched by a firefighter wearing a protective glove. Without the helmet, crews might not even have checked the part.

At the shed, firefighters were ready to break into the garage to hunt for fire. But in 10 seconds, standing 20 feet away from the building using the helmet, they determined there wasn't a threat.

Crews also can use the equipment for locating natural gas leaks and for night water rescues, allowing crews to see much further than a light will cast.

``So many times, you see advertising and you say, `This is baloney,''' said firefighter Rich Ferschke, who has worn the helmet in fires. ``This is great.''

The helmets are made by Clifton, N.J.-based CairnsIRIS, a joint venture between Cairns & Brother Inc., a private company making fire helmets since 1836, and GEC-Marconi Avionics Inc., which applied the military technology.

``We do everything as if we were blind, so now we've returned their sight,'' said Kerry Gordon, the manufacturer's product manager. ``They're no longer blind to the objects that are in there or the dangers that are in there.''

The $25,000 system went on sale in 1995, and 155 units have been bought by 100 departments.

In Maryland, a Bethesda-Chevy Chase fire rescue company is credited with the first lifesaving rescue using the system to find a burned man who collapsed in his kitchen in January.

Departments accustomed to spending $300,000 to $500,000 on a single fire truck tend to have big equipment budgets, but the helmet purchases can be costly if a department wants to place one unit on each engine.

Still, CairnsIRIS says more than 300 fire departments around the country are looking into buying the system.

``This takes the guesswork out of fires,'' McInerny said.