Steam rises off the firefighters' soot-covered coats as they move from the snowy outdoors into a darkened house crackling with fire.

But instead of rushing to the douse the blaze, a firefighter casually tosses a piece of plywood into the flames licking the ceiling.

"That'll get it going," he says to another firefighter, who nods in approval.

The firefighters let the fire burn a little more before hitting it with the hoses, because this house was built for conflagration. Called a "burn building," it has replaceable panels and is the newest training device at the Prince George's County Fire Training Academy.

More than 1,000 career and volunteer firefighters attended training classes at the academy during its recent first year of operation, Fire Chief James Estepp said.

But with the completion of the burn building in December, the facility offers a full training program for county recruits.

Previously, trainees had to travel to other jurisdictions for part of that training.

County officials are proud that their training facility, located in the southern Prince George's community of Cheltenham, was relatively inexpensive to build, largely because of volunteer help from firefighters.

It so far has cost about $300,000, compared with the $7.6 million Montgomery County spent on its training facility, officials say. "The entire department knew we needed an independent training center and knew the funds for a large capital construction project like this were not there," Estepp said. "If we had gone to the voters to build the project from the ground up, it would have cost $6 million to $7 million. By word of mouth, it . . . became a kind of labor of love."

Firefighters did much of the electrical, carpentry and plumbing work, he said.

At the academy, the firefighters practice altitude-rescue skills by climbing and swinging from a 48-foot, portable metal tower.

The tower cost about $85,000 and is the only one of its kind on the East Coast, fire officials said.

"The big thing about this place is innovation -- doing things that haven't been done before," said Lt. Michael Sweeny, commander of the training academy.

The burn building, which cost $123,000, is constructed of special panels that can be replaced at low cost, Sweeny said.

Most burn buildings are made of stone, steel and cinderblock, and wear down, Sweeny said. They must be partially reconstructed after a few years.

The burn building is equipped with furniture and a dummy in need of rescue.

"Here we're working with a controlled situation," said fire department spokesman Anthony DeStefano.

Previous trainees learned to fight fires by burning abandoned and condemned buildings slated for demolition, DeStefano said.

Another building, the "smoke house maze," is set up like an apartment.

The walls are blackened to decrease visibility and smoke is pumped in.

Portions of the building are a narrow maze through which firefighters must crawl wearing gear and masks, DeStefano said.

Firefighters also practice chopping, cutting and other tool handling skills on a demonstration roof built close to the ground, so that if a firefighter falls through, he or she only drops two feet, Sweeny said.

After the structure is destroyed, it is rebuilt with basic shingles and plywood from local stores "at a minimal cost," Sweeny said.

After recruits complete 16 weeks of training, they serve three years as apprentices at one of the county's 46 fire stations.

Career firefighters are paid a starting annual salary of $19,011.

In the next five years, the department plans to add a driving course, an auditorium, a hazardous materials training facility and a drafting pit to the training academy. Estepp said the final cost of the training center will be about $1 million.

Earlier this month, the fire department initiated a senior management training program to train firefighters in managerial skills.

Courses are taught by instructors from Bowie State College, and county officials and firefighters can receive college credit for their studies.