The Chemical Safety Board (CSB) released its final report into the June 13, 2013, explosion and fire at the Williams Olefins Plant in Geismar, La., which killed two employees.

The report concludes that process safety management program deficiencies at the Williams Geismar facility during the 12 years leading to the incident allowed a type of heat exchanger called a “reboiler” to be unprotected from overpressure, and ultimately rupture, causing the explosion.