This paper presents findings and lessons learned from the U.S. Chemical Safety Board's investigation of the 2013 Williams Olefins Plant reboiler rupture and fire. The investigation found that serious deficiencies in the site's process safety management program, including Management of Change, Pre-Startup Safety Review, and Process Hazard Analysis, were causal to the incident. This article presents lessons learned from the incident that apply broadly to the chemical process industry.


In June 2013, a reboiler that was isolated from its pressure relief valve catastrophically ruptured when heat was applied to it during an operations activity. Two operations personnel were killed. An investigation into the incident found that a series of process safety management program deficiencies over the 12 years leading to the incident caused the reboiler to be unprotected from overpressure. Weaknesses in the site's Management of Change (MOC), Pre-Startup Safety Review (PSSR), and Process Hazard Analysis (PHA) programs contributed to the incident. This article discusses lessons learned from the 2013 reboiler overpressure incident at the Williams Geismar Olefins Plant, which was investigated by the U.S. Chemical Safety Board.

Incident Background

The propylene fractionator (a distillation column) in the Williams Geismar Olefins Plant originally operated with two reboilers (Reboiler A and Reboiler B). In 2001, the site installed block valves on the shell (process) side and tube (hot water) side to allow for operation of only one reboiler at a time, with the other reboiler on standby. The tube side of the reboilers periodically fouled and required cleaning, and installing the valves allowed for single reboiler operation and continuous operation of the distillation column when the reboilers required cleaning.

The pressure relief valve for both reboilers was located on top of the distillation column. The block valves installed in 2001 could isolate the reboilers from their pressure relief valve, introducing an overpressure hazard to the reboilers (Exhibit 1). At the time of block valve installation, the site did not identify the reboiler overpressure hazard. In the subsequent 12 years leading to the incident, overpressure protection was not effectively applied to the reboilers.

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