I, Like you, would have some concerns.
Given that, I think I would ask the Fire Department because they are the ones that usually have to sign off for the insurance company.
Also, they have fought the fires that bad installations have caused.
I'm not saying that this is a bad installation but, I have never run into a situation where sawdust was the insulation.
Insurance aside, I would rather be safe than sorry!
I hopes this helps.
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