Ambulances were called to another elementary school Tuesday morning to deal with a group of children overcome by fumes.
A classroom full of students and a teacher at the École Saint-Octave in Montreal East began complaining of headaches and nausea at one point on Tuesday morning.
It wasn't quite a repeat of last week's incident at LaSalle's École des Découvreurs — there was no carbon monoxide involved, nor was a malfunctioning heating system blamed for the fumes.
Officials believe the problem in Montreal East was sulfur fumes from a nearby oil refinery which entered the classroom through the ventilation system.
This time, everyone was treated on site, and no evacuations or hospitalizations were required.
Some of the children were taken home by their parents.
On Monday of last week, 35 children and eight staff members at the LaSalle school were taken to hospital following complaints of nausea and dizzy spells because of carbon monoxide.