I worked for an electrical products distribution company ten years ago which sold mineral blanket heat shielding products made of quartz and other inorganic materials. This occurred with the banning of asbestos long ago and these products were meant as alternatives to fiberglass. I have forgotten the company's name but a web search will probably bring them up. An inquiry to them may net you a sample. I never heard of those products smoking so you must have used fiberglass, which was down the chart as far as thermal protection values went.