The dangers of pressure vessels

A good article - Accidents in Pressure Vessels: Hazard Awareness by Temilade Ladokun, Farhad Nabhan and Sara Zarei Mentions the following:  
The main causes of failure of a pressure vessel are as follows:
Faulty Design
Operator error or poor maintenance
Operation above max allowable working pressures
Change of service condition
Over temperature
Safety valve 
Improper installation
Corrosion
Cracking
Welding problems
Erosion
Fatigue
Stress
Improper selection of materials or defects
Low –water condition 
Improper repair of leakage 
Burner failure 
Improper installation

Read the article in this link.