According to the report by the state fire marshal, the moonshine still that ruptured was not designed to hold pressure and the pressure relief valve on the still was set too high.
The pressure valve was set at 150 pounds per square inch.
According to information on the moonshine still provided in the report, "Each Revenoor Still is built with a safety valve and operated on less than one pound of pressure."
State Fire Marshal Bill Swope told Local 6, "Some of the language in the report indicates that it was a vessel that was not intended to be pressurized and as a result of the process that was going on, it became over pressurized. When it became over pressurized, that energy had to go somewhere. As a result of that, that still popped off."
To read the state fire marshal's full report, click here.