A North York apartment building is being evacuated after high levels of carbon monoxide were detected, Toronto Fire says. Emergency crews were called to a building on Keele Street, near Sheppard Avenue West, at around 4 a.m. Thursday for a report of a woman experiencing symptoms of concern. Crews are still investigating the source, Toronto Fire said, but it appears to be a mechanical issue in the basement. TTC buses have been deployed to shelter displaced residents. One person was transported to hospital with serious, but non-life-threatening injuries, paramedics told CP24.