Why do LEGO parts break? I disassembled the Airplane set 7893 with normal pressure on the bricks and it happened that some parts broke like dry brittle leaves, see picture. The storage conditions have been in the open and some of the blue bricks show a bit of discoloration. I bought the set online and do not know what happened to it in last 10 years or so. The set is not that old, made 2006 or later and I wonder what can cause this weakness of the bricks?
In my experience, this happens when the lego has been washed with a too strong detergent or too high temperature...