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Valero (26003), Norco

Releases of Sulfuric Acid

LDEQ Accident Number
Accident Date
Point Source(s) Notes Amount of Release

Acid sewer line
Cause: Crack in the spent acid sewer line sent acid into soil.

Followup: Yes

Notes: The acid sewer has been removed from service. Need to test soil and groundwater and measure quanitity and disclose cause.

Acid line
Cause: Underground leak from a 4 inch fresh acid line; leak was going up out of line onto the road into a process sump.

Followup: No

Notes: All 10 gallons of sulfuric acid that spilled to the ground was
10.0 gallons

Refinery Tank Farm
Cause: Steam and acid vapor that emitted from the refinery tank farm were caused by a small leak on a fresh sulfuric acid line. The cause of the leak is under investigation.

Followup: Yes

Notes: Refinery personnel collected the spilled acid and contained it in a concrete ditch in the tank farm. Caustic soda ash was then added for neutralization. Upon neutralization, the pH was confirmed to be 7.8 and the material was pumped to the GATX pond andOutfall 006.
9,000.0 pounds

Acid pipleine in the Alkylation Unit
Cause: leak from an acid pipleine in the Alkylation Unit

Followup: No

Notes: Alkylation unit was shut down to release the pressure in the acid pipeline and stop the leak. The line is now repaired.
2,831.0 pounds

Chemical tote
Cause: a chemical tote being carried on a forklift fell on the ground and began leaking after forklift hit a pothole.

Followup: No

Notes: Material was neutralized using soda ash.
125.0 gallons
120283, 120356

Pipe to Alkylation unit
Cause: An operator discovered a leak from the fresh acid pipeline that feeds the alkylation unit. During the repair attempt residual material leaked out of the pipe and came into contact with two workers. One worker received acid burns on the neck and was treated on-site by the company nurse. the other worker received burns on the neck and face and had to be treated at Baton Rouge General Hospital.

Followup: No

Notes: Unit was shut down. After the leak of residual material, the system was purged with nitrogen, and then gravity drained to a tote tank.
230.0 pounds

Dock #2
Cause: Dock #2 - Leak from 3 small holes in 6 inch fresh 98% sulfuric acid line. Sulfuric Acid went into the Mississippi River. RELEASE INTO RIVER: OFF-SITE.

Followup: No

Notes: Still under investigation. Refinery report states they will submit follow-up report. Refinery letter only. No LDEQ report included.
4,040.0 pounds

Fresh Sulfuric Acid Pipeline
Cause: Refinery letter states that a leak developed in the fresh sulfuric acid pipeline.

Followup: No

Notes: BRQ. Refinery letter states that less than 1 barrel of sulfuric acid was released. A temporary repair was used to stop the leak. Firewater was used to rinse acid off of the pad, and the acidic wash water was neutralized in a concrete sump.

Tank: piping associated with tank 50-2
Cause: Spill from flange on the piping associated with tank 50-2.

Followup: No

Notes: BRQ. Refinery letter states that "we have determined that the spill amount was...less than the reportable quantity for sulfuric acid." Put soda ash down to neutralize the acid, cleaned up soil, repaired leak.
650.0 pounds

Tank 50-1: Sulfuric Acid Pipeline
Cause: Refinery letter states that a leak occurred in a sulfuric acid pipeline due to interior corrosion of the pipeline. Section 3 of tank area, near Tank 50-1.

Followup: Yes

Notes: RQ. Reportable quantity for sulfuric acid was exceeded. After donning protective gear, the tank farm operator immediately closed the valve to prevent any additional discharge. Personnel was mobilized to begin the remediation process. Some acid was recovered, using a stainless steel vacuum truck. The pressure indicator was removed from the fresh acid line and replaced with a blind flange. Operations will utilize the PI located on the pump discharge line for future readings. A routine visual inspection of all vents, bleeders, flanged connections, and PI's on the fresh acid system will be implemented.
1,540.0 pounds

Pressure line to T-50-3
Cause: 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.

Followup: Yes

Notes: 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.
200.0 gallons