The U.S. Chemical Safety and Hazard Investigation Board (CSB) has released a new safety video on its investigation into the fatal release of hydrogen chloride at the Wacker Polysilicon North America facility in Charleston, Tennessee, that occurred on November 13, 2020. One contract worker was killed - and two others were seriously injured - when attempting to escape the release.
The CSB's new safety video, called “No Way Down: Chemical Release at Wacker Polysilicon,” includes an animation of the events leading to the incident, as well as commentary from CSB Board Member Catherine Sandoval and CSB Lead Investigators Tyler Nelson and Drew Sahli.
The CSB released its final investigation report on the incident at Wacker on June 15, 2023. The CSB’s investigation found that at the time of the incident there were multiple contract workers present on the fifth floor of an equipment access platform at the facility. The contract workers were from two different firms, conducting different work, and were wearing different levels of Personal Protective Equipment. One of the workers applied excessive torque to flange bolts on a heat exchanger outlet pipe containing hydrogen chloride, causing the pipe to crack and release the hazardous chemical in the vicinity of the workers.
There was only one way to exit the platform – via a staircase. As the white cloud of hydrogen chloride expanded, the workers on the platform were not able to see their surroundings or access the staircase. Three of the workers who were not wearing full-body chemical resistant suits began climbing down the side of the structure to escape the hazardous cloud. All three workers fell approximately 70 feet during their attempt to escape. One of the workers died from the fall, and the other two sustained serious injuries.
In the safety video, Board Member Catherine Sandoval says, “This tragic incident was completely preventable.” She added: “What should have been fairly straightforward maintenance activity by two separate groups of workers turned deadly because of several serious safety issues. The CSB believes that our findings and recommendations will address the issues found at Wacker and prevent another needless tragedy.”
The safety video addresses four key safety issues identified in the CSB’s final report that contributed to the incident:
- The need for written procedures: Wacker tasked contract pipefitters with torquing flange bolts on a pipe segment, which contained hazardous HCl and was equipped with multiple bolts with different torque requirements. Wacker did not have written procedures for the contractors to follow and relied on the piping manufacturers’ equipment manual which did not include torque specifics for all bolts on the piping segment, and on verbal instructions for which bolts to torque.
- Control of hazardous energy: Wacker did not treat torquing operations on equipment containing hazardous chemicals as an activity that required isolation of that equipment since it did not involve the intentional opening of a line. Wacker did not perform a risk analysis and did not implement precautions to mitigate risk.
- Greater guidance on simultaneous operations: When the incident occurred, four workers from a separate contract company were performing an unrelated pipe insulation task on the same structure where the pipefitter crew was working. Wacker did not have a procedure or policy for evaluating simultaneous operations, referred to as SIMOPs, and no evaluation of risk to the other contractors was conducted.
- Improved means of egress: During the incident, a total of seven workers were present on the fifth-floor open-air platform, which was equipped with just a single point of egress. The structure was based on current building code requirements which the CSB determined do not provide for sufficient means of egress. Additionally, three months before the incident, Wacker employees identified a need for a second point of egress, but Wacker did not take any action to address this recommendation prior to the 2020 incident.
The video also highlights safety recommendations made by the CSB to Wacker Polysilicon, the Occupational Safety and Health Administration, the Center for Chemical Process Safety, the International Code Council, and the National Fire Protection Association.
About the CSB
The CSB is an independent, non-regulatory federal agency whose mission is to drive chemical safety change through independent investigations to protect people and the environment. The agency’s board members are appointed by the President and confirmed by the Senate. CSB investigations look into all aspects of chemical incidents, including physical causes such as equipment failure as well as inadequacies in regulations, industry standards, and safety management systems. The CSB does not issue citations or fines but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA. For more information, please visit www.csb.gov.
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