ROCKVILLE, Md. -- A man is dead and three firefighters seriously injured in an apartment blaze that had victims jumping for their lives early Saturday.

Firefighters arrived to find heavy flames and smoke in the three-story, garden apartment building in the 12800 block of Twinbrook Parkway about 1 a.m. Some firefighters set about rescuing residents, while other began to attack the flames.

Within five to 10 minutes, the blaze caused a "catastrophic floor collapse," sending three firefighters through the floor into a second-story room fully engulfed in flames, fire spokesman Pete Piringer said.

The firefighters issued a mayday as they tried to make their way out. Two jumped out of second-story windows and the third was able to make his way downstairs and outside.

About the same time, rescuers found a man's body in a second-floor apartment. Investigators identified the victim as 50-year-old Timothy Moran. It is believed the fire started in his apartment and that he died of smoke inhalation and burns.

Officials identified the injured firefighters as Capt. R. Dwayne Dutrow, 38, a 17-year veteran; Firefighter James Heikka, 31, an 8-year veteran; and Firefighter Mark Mechlin, who is in his 20s and has been with the fire department for about a year.

Dutrow and Heikka were flown by helicopter to Washington Hospital Center's MedStar Burn Unit, where both were listed in serious but stable condition suffering burns and internal injuries.

Mechlin was taken by ambulance to the burn unit, where was expected to be treated and released.

It was "a close call, certainly for firefighters, but also for those residents," Piringer said. The Red Cross said 53 people are displaced, but most have been able to return to their apartments now that utilities have been restored.

Eight families remain displaced and are being provided hotel rooms and financial assistance from the Red Cross.

Management at the apartment complex said it plans to provide long-term housing to the burned out families within the complex or at other nearby properties.

Investigators were on the scene Saturday afternoon, trying to determine what caused the fire, which left over $1 million in damages. It was Montgomery County's third fatal fire this year.