Boiler Explosions

Terry Welch writes about the 2001 boiler explosion of an antique tractor at the Medina (OH) Fairgrounds. Five people were killed, and many more were injured.
  The explosion was caused by an inadequate supply of water in the tractor's boiler, as well as botched boiler maintenance that deactivated plugs designed to blow before the boiler pressure reached a dangerous level.

-DD