Although Chicago is known as the Windy City, it is in fact less windy than many other major American cities. Average wind speeds range from 8 miles per hour (13 km/h) in late summer to 12 miles per hour (19 km/h) in spring months.
A flue is a duct, pipe, or opening in a chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors.
The explosion was the glass shattering. It is a sealed gas fireplace - direct vent. so no flue that I am aware of. No one sprayed anything I was home aloe on the fireplace had been on for a couple hours and I was in another room for a minute. While the glass shattered (and what I heard was like an explosion_ because it was tempered glass it did not spray the glass into the room.