What kind of "blown-in insulation?"

It's very important, health-wise, to know exactly what you have. Do not disturb this material until you know. Seriously.

If it's a loose, granular material, popular through the 1950s-60s, be very, very careful. There is a possibility that it's the type of vermiculite (or similar mineral-derived material) that has asbestos in it.

Not all vermiculite products have this problem, but IIRC one mine in the U.S. shipped out huge amounts and basically kept their mouths shut.

So you need to CYA. Just a heads-up.