Nearly 100 Montreal students whose school was the site of a carbon monoxide leak in January still need medical treatment.

According to a Global Television report, three mobile clinics set up in March by Montreal Public Health at Lasalle’s Ecole Des Decouvreurs found that 99 of the 244 children examined should consult with a pediatrician.

Public Health medical officer Maxime Roy said people exposed to carbon monoxide may experience symptoms that appear several weeks later, which is why the mobile units were established earlier this month.

The school was evacuated on Jan. 14 because of the carbon monoxide fumes, with several people being hospitalized after experiencing nausea and dizziness. Several people vomited and others lost consciousness.

The incident was attributed to a rupture in a heating system joint that had been inspected three months earlier. The Marguerite-Bourgeoys School Board said the carbon monoxide detected, which had been inspected in October and found to be in working order, was not functioning.

Four days after the leak Education Minister Jean-Francois Roberge issued a directive asking all leaders of Quebec’s education institutions to confirm the presence of gas detectors in all their buildings. He also called for air quality checks and inspections of fuel-burning facilities.