WASHINGTON (CBSDC) - Two people are in the hospital after high levels of carbon monoxide were found in a D.C. building Thursday.

The D.C. Fire Department says they responded to the report of a sick person, but when they arrived at a building in the 900 block of Ingraham Street in NW around 7:50 a.m., they quickly realized the situation was much worse.

Firefighters immediately began ventilating the building when they discovered high levels of carbon monoxide.

They say six people were evaluated by emergency response teams and two of them were moved to a local hospital to be treated for carbon monoxide poisoning.

The preliminary investigation suggests the source of the carbon monoxide is a hot water heater.

Stay tuned to ALL NEWS – 99.1 as we bring you more details.