It’s called a “slow fire,” this continuous acidification and subsequent embrittlement of paper that was created with the seeds of its own ruin in its very fibers. In a 1987 documentary on the subject, the deputy Librarian of Congress William Welsh takes an embrittled, acid-burned book and begins tearing pages out by the handful, crumbling them into shards with an ease reminiscent of stepping on a dried-up insect carcass. – Literary Hub