PROVIDENCE — A man who was critically burned in a house fire in the Smith Hill neighborhood late Sunday afternoon had been drinking alcohol and was smoking in bed when the fire began, the city fire marshal said yesterday.

“Whether he fell asleep smoking, or he just didn’t realize he had dropped” his lit cigarette, an investigation shows that the cigarette caused the mattress of his bed to catch fire, according to Fire Marshal Anthony DiGiulio.

The victim, Rainer Randell, 41, of 132 Ruggles St., was in critical condition in the intensive care unit at Rhode Island Hospital, suffering from second- and third-degree burns over 50 percent of his body, according to DiGiulio.

Randell is deaf, but there is no evidence that his impairment was a factor in the incident because there were no working smoke or carbon monoxide detectors in the house that might have alerted him, DiGiulio said.

“When the fire trucks arrived, that room was heavily engulfed in flame,” DiGiulio said.

Firefighters entered the two-story house at about 5:30 p.m. and found Randell lying unconscious in a second-floor hallway outside his bedroom.

Five adults, including Randell; Ruth Ortiz, 52, the house owner; and Donnell Ortiz, 30, son of Ruth Ortiz, lived there, according to the Fire and Police Departments. The house contained three bedrooms on the second floor, one apparent bedroom on the first floor, where Ruth Ortiz and her son lived, and one apparent bedroom in the basement, according to DiGiulio.

Flames damaged Randell’s bedroom and there was heavy water damage on the first floor below, DiGiulio reported, leaving the house temporarily uninhabitable. The Rhode Island chapter of the American Red Cross was on hand to assist the people who were displaced.

gsmith@projo.com