U.S. CSB Releases Final Report on Dow Chemical Ethylene Oxide Incident: 31,000 Pounds of Carcinogen Leaked!

It has been learned that the U.S. Chemical Safety and Hazard Investigation Board (CSB) has released its final investigation report on the July 2023 explosion, fire, and toxic ethylene oxide leak at the Dow Chemical Company's Glycol II plant in Plaquemine, Louisiana.

Around 9:15 p.m. on July 14, 2023, a series of explosions and a fire occurred in Dow's Glycol II unit, causing severe damage to surrounding process equipment and resulting in the leak of more than 31,000 pounds of toxic ethylene oxide from the plant. Ethylene oxide is a reactive and flammable chemical product and is a known human carcinogen. Local authorities subsequently issued a shelter-in-place order, affecting hundreds of nearby residents.

The CSB's investigation determined that the incident was caused by ethylene oxide inadvertently entering pressure relief piping that contained air. The mixture ignited, and the flame traveled approximately 50 feet through the piping to a pressure relief valve. Due to the resulting pressure increase, the relief valve opened, and the flame then entered the vapor space of a reflux drum containing both liquid and gaseous ethylene oxide. The gaseous ethylene oxide inside the drum decomposed due to heat, causing the pressure within the drum to continuously rise. Ultimately, the reflux drum suffered a catastrophic rupture and exploded, releasing all of its toxic contents.