Seven people have been treated for exposure to carbon monoxide at a building in the Bronx. 

It happened just before noon at a home on Grant Avenue between East 164th and 165th Streets. 

Two of the patients were in serious condition. Five others are all expected to survive. 

A defective oil burner at the location may have caused the elevated CO levels, according to the Fire Department. 

Check back soon for more on this developing story.