'Cellulose nitrate was used to make dice from the late 1860s until the mid twentieth century, and remains stable for decades. Nitric acid is released in a process called outgassing. The dice cleave, crumble, and then implode.'
Deception, Fate & Rotten Luck by Ricky Jay and Rosamond Purcell
When I was a museum curator, we knew this as 'off-gassing'. It's why you don't store lead objects in oak boxes, for example, because you end up with a box of lead oxide.
