A bulk delivery tank of sulfuric acid was inadvertently connected to a processing facility’s unmarked and open sodium hypochlorite line. It did not take long for thick clouds of overwhelmingly noxious gas to expel from the tank and engulf surrounding neighborhoods. Despite causing a shelter in place for thousands and medical evaluations of at least 120 people, fortunately, there were no severe injuries or deaths. Chemical delivery and unloading operations at facilities can involve large quantities of dangerous chemicals and the consequences of an incident can be severe. It is important to not only follow safe workplace procedures but also have visual communication in place to support a careful and responsible working environment.
“Facilities must pay careful attention to the design and operation of chemical transfer equipment to prevent similar events,” said Chemical Safety Board investigator Vanessa Allen Sutherland in a report following a review of the sulfuric acid incident in Kansas. She said the CSB strongly urges facility managers and distributors to review and adopt key lessons from incident case studies and work together to prevent future incidents.
An investigation of the Kansas incident shows there were several malfunctions of safety at play. First, out of the processing facility’s several outdoor valves, only one had an identification label. The facility’s worker who responsible for opening the sulfuric acid valve did not notice that other valves had been left unlocked. He also left the distribution worker alone to conduct the chemical unloading process. When the toxic cloud quickly began to form, the distribution worker did not have personal protective equipment on hand to allow for him to attempt to stop the chemicals from mixing further. Inside the processing facility, a PPE storage area was locked. No worker was able to gain access quickly enough before the toxic gas overwhelmed the facility.
Chemical distribution in the United States roughly equals to 39.9 million tons per every 8.4 seconds, according to the National Association of Chemical Distributors. These massive-scale deliveries result in many opportunities for chemical hazard incidents. In 2014, CSB says, there were eight incidences of inadvertent chemical connections that caused 144 injuries. In a partnership to help increase chemical safety, the CSB says it has been working with states to boost their chemical safety programs. Companies that use any of the more than 130 dangerous chemicals must comply with OSHA’s Process Safety Management standard OSHA 29 CFR 1910.119.
With large amounts of chemicals involved, it is pertinent that facility safety managers and distributers follow proper procedures and keep clear communication. Evaluate the chemical unloading equipment and processes at the facility. To reduce the likelihood of an incident, implement safeguards. Consider human error issues that could impact how facility operators and drivers interact with that equipment. Evaluate chemical transfer equipment and processes. In the process control system, install alarms and interlocks that in an emergency can shut down the transfer of chemicals. Build an effective and efficient risk assessment program by integrating facility data. To improve assessments and mitigate risk, work with chemical distributors. Develop and agree upon procedures for chemical unloading to ensure responsibilities are clearly defined. Ensure proper PPE is always organized and easily accessible by employees. Evaluate hazard control methods. Review common methods, equipment, and safe work practices that will assist in decreasing the hazards associated with chemicals. Update training standards for workers who deal with chemicals by using resources such as infographics, videos, informative articles and more. Make sure signs and labels are clear and understood by onsite workers as well as visiting workers.