An alarm sounds at the firehouse at 560 Huntington Ave., and firefighters spring into action. With sirens flashing on their firetrucks, they race to an emergency: heart attack, traffic accident, fire.
It's a scene that played out 7,084 times last year, making the Huntington Avenue firehouse — Ladder 26 and Engine 37 — the busiest in Boston.
On the southern tip of the city, some 10 miles away, firefighters in Readville logged just 574 runs last year, including many medical calls that the city's Emergency Medical Services also responds to, according to Boston Fire Department figures.
In an era of fewer blazes, firefighters at some Boston firehouses log thousands of runs, while others do very little. The busiest four firehouses, in Roxbury and Back Bay, are 10 times more active than the bottom four, located in Readville, Brighton, Dorchester, and on Long Island.
Watchdog groups that monitor city spending say that at a time of tight city budgets, the Fire Department should review its 34 firehouses to look for cost savings such as shuttering or consolidating some of the facilities.
Though many outside audits have examined other aspects of the Fire Department, none has analyzed the calls at each firehouse or examined the necessity of having firehouses in less-busy areas, they said.
All firehouses are staffed with at least one fire company — 16 firefighters, 3 lieutenants, and 1 captain — at a cost of about $2 million annually, Fire Department spokesman Steve MacDonald said. Some firehouses can have as many as 20 firefighters, he said. The department of some 1,400 firefighters, with a budget of $185 million, has not laid off a person in nearly 30 years, he said.
Meanwhile, the number of major fires in the city dropped dramatically, falling from 417 in 1975 to 40 in 2012, according to department statistics. Fire officials said the decrease is a result of factors including improved building standards and better firefighting equipment.
"Fire departments are extremely expensive, and the cost of regular staffing, overtime, and equipment are huge municipal expenditures,'' said Gregory W. Sullivan, research director at the Pioneer Institute, a conservative-leaning nonprofit, and a former Massachusetts inspector general who is reviewing the subject. "It's time to take a tough fiscal approach and consider whether there should be a consolidation at some of the firehouses that have relatively few responses compared to others."
MacDonald said firehouses are located in places where they can respond to any call within four minutes. Firehouses in more densely populated areas, especially those near hospitals and university campuses, inevitably get more calls and stay busier than those in areas with single-family houses.
"We can't predict when a fire is going to happen or when people are going to be trapped in a vehicle or if someone is going to have a heart attack," MacDonald said. "There are some fire companies that are busier than others. It's the nature of business in urban areas."
Fire Commissioner Roderick Fraser said firehouses are essential parts of the neighborhoods, and closing any one would cause a public outcry. He said it is up to the city to decide whether it wants an independent review of the department's firehouses.
"It's a political decision,'' he said. "If the mayor and the City Council want to study activity of the Fire Department, then they could.''
Cutting fire department budgets is often considered politically risky, in part because the public tends to view firefighters as heroes and because taxpayers are typically willing to pay for the reassurance of having help nearby.
The Boston Fire Department is also an agency famously resistant to change, repeatedly beating back outside efforts at reform and this year driving out a chief, Steve Abraira, who attempted to make major policy changes. MacDonald said the department's record suggests the firehouse structure works as it is.
"The fact that we have the lowest number of fire deaths in the country indicates that we have a pretty good handle on how to protect the people,'' said MacDonald.
As the number of fires dropped, medical calls have become a staple of Fire Department responses. In 2012, 60 percent of the department's 72,000 calls were medical and service-related, according to department figures. Fires accounted for just 8 percent. False and needless alarms represented 17.3 percent of the department incidents in 2012.
Firetrucks, some with defibrillators and oxygen, are often the first to arrive at certain medical calls, such as cardiac arrests, along with EMS paramedics.
Firefighters usually start basic care, including administering oxygen.
Some firehouses send two trucks to all traffic accidents, including those with no fire.
Samuel R. Tyler, president of the Boston Municipal Research Bureau, a Boston watchdog group, said that there is probably no need for the Fire Department to respond to most medical calls and that the department uses them to help justify having a large number of firehouses.
"The example that is often given to me is the Readville and the Hyde Park firehouses that are relatively close together, and yet they are still operating at costs to taxpayers that are not necessary,'' said Tyler, who is urging the city to hire an independent reviewer to analyze all firehouse activities.
"The taxpayers are on the hook because we need to have fire response and emergency response,'' said the Pioneer Institute's Sullivan.
Fire officials said that redundancies in emergency response are deliberate and necessary.
"We do have redundancies on service calls, but these are redundancies that help protect the people,'' MacDonald said.
Matt Cahill, executive director of the Boston Finance Commission, said the agency reviewed department activity four years ago and suggested cost-saving measures.
Cahill said a careful review of all Fire Department responses is long overdue.
“It’s the Fire Department,’’ said Cahill in a recent interview. “It should be fighting fires.”
Matthew Carroll of the Globe Staff contributed to this report. Meghan Irons can be reached at email@example.com. Follow her on Twitter @meghanirons.