Police found dangerous levels of carbon monoxide gas in a Warder Street home in the Northwest.
A woman called 911 complaining of breathing problems. When authorities responded at the location, they detected the high levels of gas in the air.
One man was discovered dead in the basement. Another woman was found upstairs, unconscious. The woman who placed the emergency call was found at the scene disoriented.
DC Fire and EMS spokesman Pete Piringer said that the likely cause of the high level of carbon monoxide in the air was a malfunctioning furnace in the basement. Authorities found the buildings next door found normal levels of the gas in the air.