Creating the Proximal Event Chain

While the event chain does not provide the most important causality information, the basic events related to the loss do need to be identified so that the physical process involved in the loss can be understood. 

For Citichem, the physical process events are relatively simple A chemical reaction occurred in storage tanks 701 and 702 of the Citichem plant when the chemical contained in the tanks, K34, came in contact with water. K34 is made up of some extremely toxic and dangerous chemicals that react violently to water and thus need to be kept away from it. The runaway reaaion led to the release of a toxic cloud of tetrachloric cyanide (TCC) gas, which is flammable, corrosive, and volatile. The TCC blew toward a nearby park and housing development, in a dty called Oakbridge, killing more than four hundred people. 

Rain gets into tank 701 (and presumably 702), both of which are in Unit 7 of the Citichem Oakbridge plant. Unit 7 was shut down at the time due to lowered demand for K34. 

Unit 7 is restarted when a large order for K34 is received. 

A small amount of water is found in tank 701 and an order is issued to make sure the tank is dry before startup. 

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