Even with a well documented and well practised procedure using trained staff , there is still the potential for events to spiral out of control , often due to unpredicted scenarios or a coincidence of events . There are many well documented examples of this such as : Three Mile Island accident , the Chernobyl disaster and the '' Deepwater Horizon '' drilling platform explosion in April 2010 . In a press release by BP on the 8 September 2010 , BP 's outgoing chief executive Tony Hayward said of this : The investigation report provides critical new information on the causes of this terrible accident . It is evident that a series of '' complex events , rather than a single mistake '' or failure , led to the tragedy
Three Mile Island accident
Three Mile Island accident
Emergency procedure