Boyhood Home Of Mass. Sen. Paul Tsongas Burns

The boyhood home of former U.S. Senator and Democratic presidential candidate Paul Tsongas has been severely damaged in a three-alarm fire.

Lowell Fire Department Deputy Chief Jeff Winward says investigators think Thursday's blaze was started by a carelessly discarded cigarette.

The nine residents of the three-story building on Highland Street escaped without injury. Winward says one firefighter was treated and released from a hospital for smoke inhalation.

Winward says the fire caused an estimated $100,000 in damage and left the building uninhabitable. The building is divided into five condominiums.

Tsongas, a Democrat, ran for president in 1992. He died in 1997.