"It is very prevalent in a lot of commercial buildings," Don Stefanchuk said in a recent interview, including industrial buildings, office buildings, arenas, community clubs, and hospitals. "It was the building insulation of choice back then."

"To have it tested is not an expensive deal," he said. "At a maximum, it's about $500, and that's a cheap peace-of-mind investment."

"A dozen times a year is a lot of times," Dave McNicholl said. "You have to remember, a lot of buildings don't have any (vermiculite insulation)."