On Tuesday, 23 December 2014 08:07:50 UTC, PeterC wrote:

Um, if it's mineral (rock) wool, why is it labelled as "natural"?

There's little more natural than rock!

The men weren't wearing masks and some didn't have gloves; also, no
disposable suits in evidence.
Me thinks 'twas sheepy stuff.

All mineral wools have very clear instructions about taking protective measures when installing given their fibrous construction. Whether or not they are followed is a different matter entirely.