Two people were transported to hospital Tuesday evening after a suspected carbon monoxide leak in a Centretown residence.
Thirty others were evacuated from their homes after emergency crews responded to a call just after 8 p.m., on Bell Street North near Somerset Street West.
According to the Ottawa Citizen, a technician repairing the furnace found very dangerous levels of carbon monoxide, a toxic gas that is both colourless and odourless, in the residence.
The two men were taken to hospital with symptoms of moderate carbon monoxide poisoning. A 57-year-old woman was assessed by paramedics at the scene.
Fire officials said an investigation is underway.