CSB Case Study, Video Examine 2016 Chemical Release at Processing Plant

Published January 10, 2018

The U.S. Chemical Safety Board’s case study (PDF) on the 2016 chemical release at a Kansas processing plant examines chemical transfer equipment design, automated and remote shutoff systems, and chemical unloading procedures among several key issues that contributed to the incident. According to CSB, the chemical release occurred when sulfuric acid was inadvertently unloaded from a tanker truck into a fixed tank containing sodium hypochlorite. More than 140 people, including workers and members of the public, sought medical attention as a result of the chlorine gas produced by combining the two materials. Thousands of local residents were ordered to shelter in place and evacuate. A short video on CSB’s website shows the dense green cloud that traveled from the facility toward a populated area.

CSB identified shortcomings in adherence to chemical unloading procedures and the design and labeling of the plant’s loading stations as factors contributing to the accident. On Oct. 21, 2016, a delivery truck carrying sulfuric acid was inadvertently connected to the plant loading area’s sodium hypochlorite fill line, which looked similar and was located in close proximity to the line used to transfer sulfuric acid. The agency’s investigation also found that emergency shutdown mechanisms were not in place. Design deficiencies such as the close proximity of the fill lines increased the likelihood of an incorrect connection, and chemical labels were unclear and poorly placed.

“High-risk operations, like the delivery and handling of hazardous chemicals, require strict adherence to safety protocols,” said CSB Chairperson Vanessa Allen Sutherland. “An inadvertent mixture can result in a chemical reaction with extremely dangerous consequences. Our findings reaffirm the need for facilities to pay careful attention to the design and operation of chemical transfer equipment to prevent similar events.”

CSB also released a new safety video, “Mixed Connection: Toxic Result,” which illustrates the incident using 3-D animation and includes interviews with Sutherland and a CSB investigator.

Read more on CSB’s website.