It began as a quarrel in a Northeast Washington apartment. But by the time it was over, a dramatic collision of two fire trucks had cost one fireman his leg and injured four others -- and a fire had left a family of nine without a home.

Two hours after the blaze early yesterday morning, a 27-year-old Northeast man was charged with deliberately setting a fire after D.C. police rushed the apartment where he had barricaded himself.

About 1 a.m., the fire department was called to the apartment of Velma Mitchell at 5325 Clay Ter. NE. They knew the address -- firefighters had been there two hours earlier to put out a blaze set by a Molotov cocktail thrown through a window.

And that was not the first call that night. Police had been there twice already -- responding to complaints that a man had hit Mitchell and other members of her family. Both times the man had left by the time police arrived.

When the fire alarm was sounded, Engine Company 19 set off from 2813 Pennsylvania Ave. SE and Ladder Truck 13 rolled out of 1342 Florida Ave. NE., both with sirens blaring.

Three blocks away from the blaze, Truck 13, barreling down a hill on Blaine Street NE, collided with Engine 19 on Division Avenue NE, crushing the right leg of firefighter Donald E. French, who was riding on the right side of Truck 13.

French was taken to the Washington Hospital Center, where his right leg was amputated above the knee early yesterday morning. He was listed in serious condition there yesterday.

Four other firefighters were treated for minor injuries at the hospital and released.

Meanwhile, firefighters battled the blaze that gutted Mitchell's apartment, causing an estimated $4,000 worth of damage.

Two hours later, D.C. police surrounded the apartment of Melvin Tuten at 5016 Hunt St. NE, arrested him and charged him with arson.

Fire officials said French has been with the department for 13 years. He returned to the ladder truck unit about a month ago, after recuperating from back injuries suffered in a fire.

"He's a very dedicated worker," said Capt. Gary L. Palmer.

French, who lives in Hyattsville, is divorced and has three children.

Family members gathered at the hospital yesterday to visit French following an early morning operation.

"He's a fantastic person," a niece said. "He loved his job."

Fire officials said the collision of the two fire units caused about $22,000 in damage.

Meanwhile, Mitchell spent yesterday morning trying to find an apartment for her eight children. By late yesterday, the family had hopes of moving into another housing project.

A D.C. Superior Court judge yesterday ordered Tuten held on $5,000 bond and scheduled a hearing for Dec. 27.