Four elderly residents of the Kensington Gardens Nursing Home and one employee were treated for smoke inhalation yesterday morning following a fire that forced evacuation of the home's two-story wing, according to Montgomery County fire officials.

The 10 a. m. fire, which began in one of the resident's rooms and apprently was caused by careless smoking, did about $8,000 damage to the building and $2,000 to its contents, fire official said.

A spokesman for the nursing home, located at 3000 McComas Ave., Kensington, said the wing was closed and its residents moved to other parts of the nursing home.

A 9.30 a.m. fire in a house trailer at 1001 Norwood Rd. in Montgomery destroyed the structure and its contents, causing about $41,000 damage, according to fire officials.

Volunteers from the Montgomery County chapter of American Red Cross supplied the family of four with clothing and food and helped relocate them with relatives. But both fire and Red Cross officials said the precise identity of the family was not known.

Arlington County fire officials reported that seven persons were slightly injured early on New Year's Day by a fire in a high-rise apartment building.

Officials said the blaze, apprently caused by a age to an apartment at Buchanan House, located ar 2301 Jefferson Davis Highway.

Fire officials said one person in the apartment suffered slight burns to his neck and ears. Six others persons visiting the unit were treated for smoke inhalation at Arlington Hospital and released.