industrial accidents involving heat exchanger

In last June 2008, an industrial accident involving heat exchanger occurred at the Goodyear Tire and Rubber Company in Houston, Texas. The heat exchanger ruptured and released toxic chemical, ammonia, and caused one employee died. Another five employees got injured due to ammonia exposure.
According to Chemical Safety Board (CSB) investigation, the accident occurred because of overpressure inside of the heat exchanger. Ammonia inside of it was heated by steam and valves next to the relief valve and automatic pressure control valve were closed.

Why Such Accident Occurs

The accident occurred because of miss-operation before maintenance work was done for that heat exchanger. Overpressure is one of failure modes associated with heat exchangers. There are other factors that can cause industrial accidents involving heat exchanger such as design fault, corrosion, external event, erosion, fire, explosion, maintenance fault, overheating, structural failure and defective equipment.