The smoke passengers saw coming from the air vents of the Boeing 737 was vapor from excess de-icing fluid. The smell described by the passengers was similar to engine coolant. Oxygen masks did not deploy.

The pilot returned to the runway at 7:00 a.m. No smoke or fire was found (obviously) because the vapor was not smoke at all, but evaporating coolant that had gotten into the plane via a vent.

The investigation is ongoing.

The post First findings: Sunwing Diversion Due to Fumes not fire first appeared on George Hatcher's Air Flight Disaster.