health aspects of exposure to thermal insulation
I'm guessing you're talking about fiberglass. I usually wear a mask if I go in my attic for a long time, and wear gloves if I will be working with it. While it has not been proven harmful, asbestos was nor proven harmful some 40 years ago either. Best to play it safe. Though my guess is that with things being more advanced now if it was harmful they probably would have discovered it by now. I would imagine someone who is exposed to it day by day would really need to wear more PPE though just because of the constant exposure.
I just find if I go in my attic without a mask I start coughing up and have a really itchy throat. Worse if I go in the summer when it's hot in there.
If I need to deal with moldy insulation I usually just spray Benifect on it and try to move out out as fast as possible without rushing it, and if I'll be moving a lot of it I'll wear a mask too.