Sulfur Tank Ejects Vapor at Wilmington Refinery

By Christian L. Guzman, Contributing Reporter

The Tesoro Corp. has yet to determine the cause of the Aug. 26 sulfur tank breach at its Los Angeles Refinery.

The tank was being used to store molten sulfur. After the lid of the tank was breached, a plume of gases escaped from it. The tank’s insulation caught on fire.

Along with Tesoro, the Los Angeles County Fire Department and the Los Angeles County Sheriff’s Department responded to the incident.

The fire was extinguished before the tank was significantly damaged. No injuries due to the tank breach were reported.

The sheriff’s department ordered businesses and residents within a quarter mile to “shelter in place,” while responders surveyed the damage due to the breach. This means buildings were to be sealed by closing doors and shutting windows, so that harmful gases could not easily enter.

Jesse Marquez, executive director of Coalition for a Safe Environment said that this technique is only effective if buildings are sealed immediately after an incident. If a building were to be sealed after gases already diffused inside, occupants could actually be harmed more than if the building were not sealed at all.

The South Coast Air Quality Monitoring District conducted air monitoring and sampling of the surrounding area. The district concluded that harmful levels of toxic chemicals were not present.

The refinery continued to operate while the tank was being inspected.

Marquez said that knowing the type of breach will help investigators focus on its cause. The two main types of tank breaches are cracks or ruptures. Both can be brought on by external and internal factors. However, cracks are more likely due to metal fatigue of the tank over time. Ruptures can be caused by something more immediate, such as a bolt hitting the tank.

Tesoro is coordinating with the California Division of Occupational Safety and Health to determine the cause of the tank breach, as well as the exact type of breach.