An explosion in an LNG storage tank in the process of being repaired could have occurred as the result of static electricity, malfunctioning electrical equipment, an open flame in contact with the liner, or purposeful action (industrial sabotage). Interviews with engineers who were analyzing the risks involved led to estimates that such a explosion would occur with probability 0.25 as a result of static electricity,0.20 as a result of malfunctioning electric equipment,0.40 as a result of an open flame, and 0.75 as a result of purposeful action. These interviews also yielded subjective estimates of the prior probabilities of these four causes of \(0.30,0.40,0.15\), and 0.15, respectively. What was the most likely cause of the explosion?