In early October 2010, health authorities were notified to "address the health issues" affecting preschool and elementary school teachers at a private school (fatigue, migraines, ear, nose, and throat irritation, etc., leading to sick leave). These symptoms had persisted intermittently since September 2009, before spreading to the majority of the staff, leading to the evacuation of the premises. All stakeholders were brought together in an interdisciplinary coordination team to share available information, coordinate relevant investigations (medical examinations, individual interviews with a psychosocial counselor, descriptive epidemiological survey, environmental assessment), and propose appropriate management measures. Air analyses revealed that the premises were poorly ventilated, leading to high CO2 levels in the classrooms. Concentrations of the other pollutants tested were within normal ranges. The psychosocial investigation revealed that the combination of several serious health incidents at the school had generated significant anxiety; in the absence of clear communication from the administration and a response to staff complaints, this had convinced the staff that being on the premises posed a risk to their health. The epidemiological investigation concluded that there was no danger, with most symptoms attributable to the lockdown. The crisis was resolved through technical repairs to the building and improved communication. (R.A.)