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Louisiana Refinery Accident Database

Valero (26003), Norco

LDEQ Accident Report

Pollutants Released

Accident Classified As: No Information Given

Cause of Problem: Seal or Gasket

After an investigation, it was determined that the spill on line T-50-3 was due to a gasket failure that resulted from thermal expansion of a liquid in a fixed length section of pipe. The incident occurred during a regulatory pressure test, where an area of pipe containing spent sulfuric acid was blocked between two closed valves. The ambient temperature was above 90 degrees F, and heat from the sun caused the material in the pipe to increase pressure. The abnormally high pressure from thermal expansion pushed the gasket and, in the absence of a thermal relief valve, caused the gasket to malfunction.

Discharge Preventable - Yes

Notes/Remedial Actions

As a precaution, hand held air monitoring devices were used within the refinery (with respect to wind direction), along River Road and Prospect Ave. See note. Most of the acid that was spilled into the containment was removed using a vacuum truck. Soda ash was used to neutralize any residual acid in the area. The contaminated soil was excavated and stored in rollout boxes and properly disposed. We will implement the following corrective actions a result of incident investigation: 1) Modify the piping system at the tank to include a thermal relief system. 2) Modify guidelines to reflect thermal expansion as an issue during this test. 3) Review the incident with affected personnel, and train them on the hazards associated with thermal expansion. 4) Ensure piping of new tank in similar service has proper relief. Note: Readings for CO, H2S, VOC, and SO2 read 0 ppm at multiple sites downwind (north/northwest of the incident). Nuisance odor was present near the FCCU. The onsite air monitoring station was continuously taking SO2 readings, although this is located in the southeast of the area, which is the opposite of the wind direction during the event. The readings for this area were on average 2.1 ppb at the time of the incident and throughout the cleanup process.