February 14, 2019

"Thermal Fatigue" Led to 2016 Mississippi Gas Plant Explosion

​A final report released yesterday by the U.S. Chemical Safety and Hazard Investigation Board identifies “thermal fatigue” as the cause of the June 2016 explosion at the Enterprise Products Pascagoula Gas Plant in Pascagoula, Miss. According to the report, the failure of a piece of equipment known as a brazed aluminum heat exchanger, or BAHX, led to a release of hydrocarbons including methane, ethane, and propane. The ignition of the hydrocarbons caused a series of fires and explosions that closed the plant for six months. No fatalities or offsite property damage resulted from the incident.

Heat exchangers expand and contract as their metal components are alternately heated and cooled. Over time, this process caused cracks in the BAHX at the Enterprise plant, which allowed the hydrocarbons to escape.

“More than 500 gas processing facilities operate across the country, and the use of similar heat exchangers is common,” said Kristen Kulinowski, CSB’s interim executive. “Extending the life cycle of equipment at these facilities requires more robust inspection protocols. Operators shouldn’t take the risk of waiting to find a leak because, as this case demonstrates, that leak could result in a catastrophic failure.”

According to a CSB press release, the BAHXs at the Enterprise plant were subjected to stresses that exceeded recommended industry practices. Similar incidents in other plants indicate that gas plant managers should not assume heat exchangers will leak before they fail, the agency cautioned.

“A number of midstream gas plant operators have reported that the limits and rates in existing industry guidance may not be realistic,” said CSB investigator William Hougland.

CSB recommended that the American Petroleum Institute and the GPA Midstream Association, an industry group, share information related to the hazards of BAHX failure.

Visit the CSB website to read the full report (PDF). An animation of a heat exchanger is also available.