The incident occurred shortly after 4:30 am on January 23, 2020, when an accidental release of propylene accumulated and exploded inside the building. The CSB found that before the incident, a hose disconnected from its fitting inside a coating booth and released propylene, a flammable hydrocarbon vapor, which accumulated inside the coating building. When employees arrived at the facility early on the morning of January 23, an explosive concentration of propylene had formed inside the building. When one of the employees entered the building and turned on the lights, the flammable vapor ignited, triggering the explosion.
CSB released its final investigation report on the 2020 propylene release and explosion at a grinding facility in Houston, Texas, that fatally injured two workers and a nearby resident and damaged hundreds of neighboring homes. The CSB’s final report highlights several safety issues: