CSB Examining Mechanical Integrity in Investigation of 2023 Chemical Release
The U.S. Chemical Safety and Hazard Investigation Board (CSB) is examining mechanical integrity policies and practices as part of its investigation of an explosion and release of hydrogen fluoride and chlorine gas that occurred when a reboiler catastrophically ruptured at the Honeywell facility in Geismar, Louisiana, in January 2023. The facility manufactures refrigerants and other products, and the unit involved in the incident manufactures 1,1,1,3,3-Pentafluoropropane, or HFC-245fa. No workers were injured from the explosion and release, but the incident led local officials to close nearby highways and for workers to shelter in place at the facility. The estimated property damage was $4 million, and the HFC-245fa unit involved in the explosion was shut down for 47 days. CSB’s investigation update (PDF) describes some of the events leading to the reboiler shell’s failure.
According to CSB’s report, Honeywell had most recently conducted mechanical integrity inspections of the reboiler that failed in September 2020 and October 2021. In 2020, the company used ultrasonic thickness testing to estimate that the reboiler shell had 1.1 years of service life remaining, and in 2021 the inspection involved an internal visual inspection of the reboiler. Following the 2021 inspection, Honeywell personnel recommended that the reboiler shell be replaced at the next shutdown opportunity. The company initiated a project to purchase a replacement boiler shell in January 2022, but CSB found that management did not purchase or install a replacement shell before it failed in the next year in January 2023.
The conditions inside the reboiler when it failed led to a boiling liquid expanding vapor explosion, CSB explains. The resulting release included 871 pounds of hydrogen fluoride, 1,684 pounds of chlorine, 1,754 pounds of FC-245fa, and 220 pounds of various process intermediates, according to the agency. CSB’s findings so far have prompted investigators to focus on “key areas” such as Honeywell’s policies and practices related to mechanical integrity and project management as well as relevant facility, corporate, and industry standards.
CSB’s investigation is ongoing. More information can be found in the agency’s press release, and future updates will be available via the incident page on the CSB website.