When Thomas W. Carr Jr. became a firefighter in Montgomery County in 1973, the job description for fire chief was fairly straightforward: Fight fires. Tend to the department's budget. Fight more fires.

Now, as a candidate for county fire chief in the post-9/11 world, Carr must sell himself as equal parts politician, safety advocate and homeland security guru. Firefighting tends to be a small part of the modern chief's portfolio, experts say.

"At one time, fire departments fought fire and that's just about it," said Garry L. Briese, executive director of the International Association of Fire Chiefs. "Now you have weapons of mass destruction, terrorism response, emergency management. The list goes on and on."

The growing complexity of leading a large urban-suburban fire department is compounded in Montgomery. The county recently established a single chief's post to oversee a service deeply divided between career and volunteer firefighters -- a consolidation most major departments undertook decades ago.

As the first person to have authority over the entire fire service in Montgomery, the new chief, whom officials expect to select by the end of the month, will have to soothe bitter feelings left from a year-long battle over creating the position.

The fire service in Montgomery has for years been governed by a tangled web of authority that includes 19 volunteer chiefs, a career chief, a seven-member fire commission and a civilian fire administrator.

The County Council changed that in May, voting unanimously to create a single career fire chief to oversee the department's 1,000 career firefighters and several hundred volunteers. (County officials say the number of volunteers who regularly participate is about 400; volunteers say the number is closer to 900.)

Volunteers, who retained significant clout in Montgomery long after their counterparts in other jurisdictions were overshadowed by career firefighters, objected to the single career fire chief, saying it would undercut their authority.

Carr, who has been chief of the county's career firefighters since 2003 and lobbied heavily for the legislation creating a single fire chief, is considered a leading candidate by several members of the County Council. Officials declined to disclose candidate names, but Carr acknowledged he has applied for the job.

In e-mails and community forums, Montgomery residents have in recent months described their ideal candidate as someone who is sensitive to racial and ethnic differences; who will be a strong hand in the event of a disaster; and who can navigate the hazards of integrating volunteer and career firefighters under a single command.

In short, a fire chief who looks nothing like the fire chiefs of 20 or 30 years ago.

"When I first came into the fire service, it was kind of a mystery to everyone what the fire chief did," said Russ Sanders, executive secretary of the Metropolitan Fire Chiefs Section of the International Association of Fire Chiefs and a former Louisville fire chief. "The chief was kind of left in the dark, and you let him do his thing."

That began changing in the 1980s, Sanders and others said, when fire departments started handling more emergency medical calls. Routine response to dire medical situations brought firefighters and commanders into more direct contact with the community -- and politicians.

"Politicians started thinking, 'We can't just make anybody fire chief,' " Sanders said.

Sept. 11, 2001, raised the importance of fire chiefs even more dramatically, as they became an integral part of many communities' terrorism-response plans.

Fire chiefs also are expected to be higher-profile than they once were, experts said, and now often take on the level of public scrutiny once reserved for police chiefs.

That has created a kind of star culture among fire chiefs nationally, with well-known chiefs getting the same kind of courting from potential employers as chiefs of police and school superintendents, experts said.

"There's an increasing realization among government [officials] that the fire chief is a key position in local government," Briese said.

The Washington area has had significant recent turnover at the top levels of fire agencies. Among the largest jurisdictions in the region, no fire chief has been in office for longer than three years. Last week, Prince George's County Fire Chief Ronald D. Blackwell announced that he was leaving after three years at that department's helm to become Anne Arundel County's fire chief.

In addition to the challenges of coordinating disaster response with agencies across the Washington region, Montgomery's new chief will have to cope with a number of internal problems, including an aging and poorly maintained fleet of vehicles and a recruit class this year with the lowest number of minorities since at least 1988.

County officials have said the low minority numbers -- white men account for 89 percent of the current class -- resulted from recent changes in hiring policies, and they pledged to change the process to encourage more minority applicants.

Fire officials told County Council members last week that nearly half of the county's fire engines were out of service for seven or more days in one recent month.

Because of the department's decentralized authority, volunteer fire companies have for years overseen maintenance and repair for apparatus stationed in their firehouses. But the county's fire service increasingly responds to emergencies as a countywide unit, with equipment moving for long periods between volunteer firehouses.

There is no centralized system to track maintenance and repair of county apparatus. Creating such a system will take money and the cooperation of the volunteer fire companies, officials said. In theory, the new fire chief will have the authority to implement countywide programs. But with a department culture accustomed to giving much authority to volunteer chiefs, it may be more difficult than it looks on paper, officials said.

"You can't snap your fingers and say, 'There's got to be trust' " between volunteer and career staff, Carr said in an interview. "There's a perception that there's not 100 percent trust, so you just have to build those relationships."

Thomas W. Carr Jr. is chief of Montgomery County's career firefighters and a candidate for the top job.