CD exploded in the drive?!? How?

OK so this is a first for me. Got a call from our receptionist this morning saying that a cd a exploded in her cd drive.

Apparently she put the cd in the drive and walked into the next room. She said she heard a really loud crash. She actually thought one of the plants in her office had fallen off the file cabinet it was so loud. When she opened the cd drive pieces of the cd fell out.

Now ive broken many a cd in frustration and those things arent that easy to break, and they usually dont shatter like that, just crack.

Anyone heard of this, any ideas why it would happen? has me really curious….