Public health officials set up follow-up clinics to screen 244 students at a LaSalle school who were exposed to carbon monoxide poisoning in January and close to 100 of them were sent to see a specialist.

An investigation into possible criminal negligence has been opened into the Jan. 14 carbon monoxide leak that sent more than 40 people to hospital.

This week on Focus Montreal, we learn about the importance of having carbon monoxide detectors in schools, as well as what's being done in Montreal to help the homeless find shelter from the cold.