Chemical Safety Board finalizes two fatal accident investigations

The US Chemical Safety and Hazard Investigation Board on Sept. 24 approved two final reports on accidents that killed six workers. The reports were critical of AB Specialty Silicones of Waukegan, Illinois, where four workers were killed May 3, 2019, and an Evergreen Packaging paper mill in Canton, North Carolina, where two workers died Sept. 21, 2020.

The silicones plant was making a silicon hydride emulsion when a flammable vapor cloud developed and ignited, causing an explosion and fire. In addition to the deaths, a fifth employee was seriously injured. The CSB found that workers inadvertently mixed several incompatible chemical compounds that were stored near each other in nearly identical drums, generating hydrogen gas that ignited.

The facility lacked an adequate ventilation system and a working alarm system, the CSB noted.

At the meeting announcing the reports, CSB chairperson Katherine Lemos said that reactive chemicals, such as those used by AB Specialty Silicones, are regulated by neither the US Occupational Safety and Health Administration nor the Environmental Protection Agency. For more than 20 years, she stressed, the CSB has urged the agencies to regulate such chemicals.

At the paper mill, an electric heat gun fell into and ignited a bucket of flammable resin during a scheduled maintenance operation. The heat gun was not permitted in the work area but workers were using it to speed up their cleanup and maintenance operation. Such hot work was not allowed in the confined space area, and the workers lacked a fire extinguisher.

The maintenance operation was conducted by two sets of contractors from two separate companies. The contractors violated several procedure concerning hot work and working in confined spaces, the CSB noted. The two teams lacked coordination and shared communication while working on adjacent but separate maintenance operations, a situation that complicated and contributed to the disaster.

The CSB has investigated several similar accidents concerning hot work and confined spaces and has urged companies and regulators to increase their attention to these areas, Lemos noted. “We hope that these new reports and investigations will further inform industry about the risks inherent to these activities and how those risks can be successfully mitigated.”

CSB’s findings, conclusions, and recommendations were presented by staff orally with a slide presentation at a 4-h virtual hearing attended by 150 people. The public was unable to ask questions or comment at the hearing, and neither the reports nor the slides had been released publicly as of C&EN’s deadline.

The reports will be released “in coming weeks,” the CSB says.

The CSB’s board currently has only one member, Lemos, who questioned the staff and approved the reports. The CSB has another 18 unfinished accident investigations, stretching back 5 years. President Joe Biden has nominated three more people to the board, and they are awaiting Senate confirmation.