A safety video focuses on the October 21, 2016, toxic chemical release at the MGPI Processing facility in Atchison, Kansas, which resulted in over 140 reported injuries, and approximately 11,000 citizens forced to evacuate or shelter-in-place.
The release occurred during a routine chemical delivery when two incompatible chemicals – sulfuric acid and sodium hypochlorite – were inadvertently mixed, forming the toxic cloud.
The Chemical Safety Board’s (CSB) safety video entitled, “Mixed Connection: Toxic Result,” includes a 3D animation of the incident, as well as interviews with a CSB investigator and Chairperson Vanessa Allen Sutherland.
“Delivery and unloading operations may be perceived as simple compared to other processes at chemical facilities, but because these activities can involve large quantities of chemicals, the consequences of an incident can be severe,” Sutherland said. “Our case study on the MGPI incident stresses that facilities must pay careful attention to the design and operation of chemical transfer equipment to prevent similar events.”
At MGPI a truck from a chemical distribution company, Harcros Chemicals, arrived on the morning of October 21, 2016, to complete a routine delivery of sulfuric acid. An MGPI operator escorted the driver to a loading area where he unlocked the sulfuric acid fill line for the driver to connect the truck’s hose.
But the sodium hypochlorite line was also unlocked, and the two lines, which were only 18 inches apart, looked similar and were not clearly marked. The driver inadvertently hooked the sulfuric acid hose to the sodium hypochlorite fill line and the two chemicals mixed, forming a dense cloud containing toxic chlorine gas and other chemicals.
In the video, investigator Lucy Tyler describes three key lessons learned from the MGPI incident. They are:
• Facilities should evaluate chemical unloading equipment and processes, and implement safeguards to reduce the likelihood of an incident. This should be done while taking into account human factors issues that could impact how facility operators and drivers interact with that equipment.
• Facility management should evaluate their chemical transfer equipment and processes and, where feasible, install alarms and interlocks in the process control system that can shut down the transfer of chemicals in an emergency.
• And facilities should work with chemical distributors to conduct a risk assessment and then develop and agree upon procedures for chemical unloading to ensure responsibilities are clearly defined.