Bismark, ND – Two residents in Bismarck are recovering at a local hospital following carbon monoxide poisoning at their home.

The Bismarck Fire Department says firefighters were dispatched to a Bismarck home about 2:30 a.m. Wednesday following a report that two residents had become sick from carbon monoxide.

Firefighters treated the two residents before they were transported to a local hospital.

Officials say the carbon monoxide was coming from the boiler for the hot water heater. The boiler had not been burning or venting properly.

The fire department is recommending that building owners have a licensed contractor inspect heating systems regularly.