STAMFORD-A fire that destroyed the bedroom of a historic house in North Stamford Wednesday morning was touched off by a candle that came into contact with oxygen being used at the time, fire officials say. Stamford Chief Fire Marshal Charles Spaulding said that a candle burning in the bedroom of a home at 509 Long Ridge Road came into contact with a tube leading from an oxygen tank being used by the 50-year-old female owner of the home. “The oxygen tube touched the candle, causing the flame to flare up and ignite the linen bedding,” Spaulding said. The woman and a man, who was sleeping in a separate room in the house escaped, although the woman suffered a burn to her lower leg, Spaulding said.