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Someone at work got a new office. He decided he wanted a second door and tunneled through the wall to make it.
(hexbear.net)
This wall was to the supply room with all of the uniforms and PPE. The building was constructed in the mid-20th century so it turns out it's full of asbestos. Thanks mole man.
The only materials you can safely assume are 100% NOT ASBESTOS are wood glass and metal.
It is fireproof, waterproof(amphibole asbestos is anyway), resists electricity, is the best insulation material on earth still used in space applications, it's lightweight, it comes from the earth as Asbestos it needs no processing other than like grinding it up, it's indestructible, easy to work with, as it "deteriorates" it keeps its fibrous shape just gets longer so it lasts forever.
If it didn't kill you slowly it would be the best material known to humankind.
The cost to safely abate the least dangerous forms of asbestos are massive. Not even just in money. The amount of poly plastic needed, the wasted coveralls, the duct tape. It's an environmental nightmare to make a high risk enclosure but even in a moderate risk you're using like 3 coveralls per person per shift