WASHINGTON — High levels of carbon monoxide were found inside a three-story building on the 500 block of U St. in northwest D.C. Sunday morning.

Eight people from that building were transported to local hospitals, all with not life-threatening injuries.

The source of the carbon monoxide was traced to a furnace in the building.

D.C. fire and EMS remind residents to check that they have working carbon monoxide detectors in their homes.

For information on recognizing symptoms of carbon monoxide poisoning, visit the CDC website.