Shortly before 9:00 am on the morning of August 23, 2010, Millard was in the process
of loading two international ships with frozen poultry when the facility’s refrigeration
system experienced a hydraulic shock event that lead to a catastrophic piping system failure
and the release of 32,100 pounds of anhydrous ammonia. The majority of the ammonia
released in this incident occurred through a compromised portion of the system’s 12-inch
suction pipe located on the roof (Figure 1). The resulting cloud of ammonia vapor traveled
0.25 miles to the south across the Theodore Industrial Canal, exposing a Millard employee
and offsite contractors working outdoors.4
At approximately the same time, alarms
sounded within the plant due to the detection of high concentrations of ammonia indoors
by air-monitoring equipment in the freezers. The ammonia detected within the facility was
the result of a second leak that developed because a portion of the system’s blast freezer5
evaporator header ruptured (Figure 2).