I wonder in what respect you are suggesting that they are under the 'unsafe limit'? Air sampling? I would assume you would dispose of this as 'asbestos waste'. This isn't the Belgrano files is it? I recall that some years ago the government had declined the release of information relating to the sinking of the Belgrano, as the room in which all the paper work was stored was contaminated with asbestos. No political point being made - just a little 'elf and safety' or is it FOI tale for a Friday :-)

Been there - had to dispose of tons of paper records that had minimal contamination but was still classed as "asbestos waste"

No mate - the entire contents of the area in question went as asbestos waste - paper, books, furniture, the lot! But under controlled conditions of course - area sealed, tested, waste was bagged and taken out through the air lock to the controlled waste skip

Having worked with old books before now - not a comment on the backlog of academic catch-up across my desk but several commissions to assess fungal contaminants and distinguish between regular foxing and more preventable fungal contamination associated with specific building-related issues - I must question this strange idea of air sampling. How, where and when was this done? Creeping up on said books, as if about to shout Boo! Standing over them, casting a deep shadow on their slumber? Or perhaps looking admiringly as they stand proud on a shelf? The problem with books is that they gather dust, and lots of it. When picking up old books readers tend to see this and either fan and flick the pages or blow with puckered lips, in either case to create a local, and inevitably dense, cloud of dust just in front of their faces. Did your air sampling assess this?