Video Depicts 2020 Propylene Release and Explosion at Manufacturing Facility

A new animated video from the U.S. Chemical Safety and Hazard Investigation Board (CSB) depicts the events that led to a release of propylene and subsequent explosion at the Watson Grinding and Manufacturing Company facility in Houston, Texas. The incident on Jan. 24, 2020, killed two workers and a member of the public and resulted in damage to more than 450 homes and buildings in the surrounding neighborhood.

Workers at the Watson facility performed high velocity oxygen fuel coating, which involves the use of propylene, a highly flammable gas. A CSB final report found that on the night before the incident, a degraded, poorly crimped rubber hose became disconnected from a fitting inside a coating booth. By the next morning, an explosive concentration of gas had accumulated inside the building and probably ignited when a worker arriving for the day turned on the lights.

Among other shortcomings, the facility’s automated system for detecting leaks, sounding alarms, and starting exhaust ventilation had been disconnected years earlier, CSB found. Additionally, shutoff valves at the propylene storage tank had been left open the previous day. CSB determined that Watson did not conduct a hazard analysis of the propylene gas system and did not train its employees on how to respond to a propylene leak.

The CSB video is available on YouTube. For more information, read the agency’s final report (PDF).