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Valero (26003), Norco

Causal Factor: Maintenance/Procedures

LDEQ Accident Number
Accident Date
Point Source(s) Notes Amount of Release
No LDEQ Reported

Reactor drums
Cause: During demolition project involving five reactor drums purchased by the previous owner of Valero Refinery, a previous enclosed layer of asbestos containing insulation material revealed.

Followup: Yes

Notes: Valero's response to OSHA complaint alleging hazards - asbestos release into air exposing employees. Demolition ceased and abatement scheduled according to regulations.


None Reported
Cause: MSCC fractionator overhead receiver started venting to flare as result of the unit being shut down for a mechanical repair to the hot stripper side valve.

Followup: No

Notes: Letter states that emissions were BRQ.

fluidized catalytic cracking unit (FCCU)
Cause: Valero shut down the fluidized catalytic cracking unit in a controlled shut down process.

Followup: No

Notes: Completion of repairs to some units were made, then they started up units. They said they would follow up if anything abnormal were to happen.


None Reported
Cause: In the process of shutting down the FCCU, Valero noticed and reported ongoing intermittent flaring.

Followup: No


fluidized catalytic cracking unit (FCCU)
Cause: Valero shut down the fluidized catalytic cracking unit in a controlled shut down process.

Followup: No

Notes: No information given.


fluidized catalytic cracking unit (FCCU)
Cause: Valero shut down the fluidized catalytic cracking unit in a controlled shut down process to repair flue gas cooler.

Followup: No

Notes: No information given.


Flares 1 and 2
Cause: while conducting maintenance on the steam system on the compressor, the WGC tripped on low lube oil pressure

Followup: No

Notes: Emissions minimized by immediately restarting WGC
Sulfur Dioxide: 3,660.0 pounds

Flares 1 and 2
Cause: MCCU was shut down so that a pinhole leak on the Millisecond Cat Cracker unit could be repaired

Followup: Yes

Notes: A plug was installed to minimize the leak.

Sulfur Dioxide: 425.0 pounds

Cause: while initiating corrective actions for another incident the WGC tripped.

Followup: No

Notes: Emissions minimized by immediately restarting WGC.
Sulfur Dioxide: 7,800.0 pounds
Carbon Monoxide: 213.0 pounds
Volatile Organic Compounds: 81.0 pounds
Nitrogen Dioxide: 39.0 pounds
Hydrogen Sulfide: 21.0 pounds

East Plant
Cause: East Plant coming down for a scheduled maintenance turnaround

Followup: No

Notes: Courtesy notification of scheduled turnaround


Tank T-150-2
Cause: personnel digging holes around tank T-150-2 to place covers over the grounding leads around tank notice diesel leaking from these holes.

Followup: No

Notes: Refinery personnel used absorbent boom and vacuum trucks to contain and recover the material.


Flares 1, Flare 2
Cause: While performing a preventative maintenance check. While checking voltage output levels on the power supplies in the control cabinets an arc was created that shut down both power supply #1 an #2. The loss of both power supplies caused the redundant controllers to power down, which shutdown the Coker Wet Gas Compressor sending material to the flare.

Followup: Yes

Notes: Wet gas compressor was immediately restarted
Sulfur Dioxide: 4,241.5 pounds
Carbon Monoxide: 106.9 pounds
Nitrogen Dioxide: 19.6 pounds
Volatile Organic Compounds: 40.4 pounds
Hydrogen Sulfide: 11.3 pounds
Particulate Matter: 0.8 pounds


Cause: The release occurred to purge the chemicals that had contaminated the caustic system used for pH control at the wet scrubber. This caused unpleasant odors.

Followup: No

Notes: N/A


Cause: This was a hydrostatic test discharge for a storage tank that used a biodegradable colorant (green). According to Valero, the hydrostatic test water was sampled and met LPDES permit limits for this activity.

Followup: No

Notes: BRQ. No information given.


FLARE: Flare #1 & #2, MSSCU, SRU, 3700 TOX
Cause: Flaring caused by difficulty starting up the Millisecond Catalytic Cracking Unit (MSCCU), as well as the Sulfur Recovery Unit (SRU) and its related thermal oxidizer (TOX) after a maintenance shutdown. Some emissions exceeded visible emissions and opacity permit limits as well.

Followup: Yes

Notes: RQ. Refinery letter states that reportable quantities were exceeded for sulfur dioxide, nitrogen oxide, and hydrogen sulfide. Initial refinery letter, plus two additional follow-up reports included in file. Remedial actions: "Maximized steam to flares to mitigation visible emissions...and adjusted feed rates and other process parameters in order to complete startup and stabilize the MSCCU and 3700 SRU units." "A minimal amount of waste gas is expected to be flared during process startup. Currently this activity is permitted for expected losses of criteria pollutants and hydrogen sulfide. Since the loss of propylene is not permitted under startup emissions, but is expected, Valero will request propylene allowances in a future application for a permit modifications. Additionally, we are planning to install flare gas recovery compressors on Flares 1 and 2 in the year 2011. These compressors will have the ability to capture waste gasses generated from startup activities and return them to the refinery fuel gas system."

Sulfur Dioxide: 34,598.0 pounds
Hydrogen Sulfide: 613.0 pounds
Propylene: 19.0 pounds

Flare 1
Cause: On November 11, 2013, the Valero St. Charles Refinery experienced flared while making repairs on the Coker Jet Pump, which supplies water to the coke drums during the coke cutting process. Portable pumps were installed during the repairs but kept tripping due to vibration issues. Therefore, we cut feed to the coker and the heaters were put on circulation. The decreased fee into the Coker Unit from the Vacuum Unit caused the Wet Gas Compressor (WGC) to trip, which caused flaring. When the WGC tripped, pressure started to build up on the Vacuum Jet Receiver. To prevent the Vacuum Jet Receiver pump from tripping and causing a loss of vacuum in the vacuum distillation column, the backpressure on the jet receiver was relieved to the flare until the WGC stabilized. The pressure control valve on the vacuum jet receiver was open to the flare for approximately one hour, but intermittent flaring ensued until the rates in the coker unit could be increased to provide the WGC with enough gas to operate normally.

Followup: Yes

Notes: First written report states that emissions were minimized by reducing rates and installing a spare vacuum jet overhead pump. The incident occurred due to the inability to maintain operation of the COker WGC which pulls gases from the Coker and Vacuum Units. While the WGC was down, the Vacuum Jet Receiver was vented to the flare in order to maintain unit operation and avoid a larger flaring event associate with the unit trip. Additionally, the Flare Gas Recovery Unit remained in operation to reduce the amoin of flared gas. The event was secured by completing repairs on the coker and stabilizing the WGC. The following corrective measures were taken to prevent recurrence: 1) Review this incident with affected personnel. 2) Evaluate the piping system for use with temporary jet pumps and redesign as needed to minimize vibration issues. 3) Develop a reliability improvement plan that is based on the findings of the investigation into the jet pump failure. 4) Implement a reliability improvement plan on both in-service and spare coke cutting pumps. 5) Review the WGC operation for continued use at low rates or when the Coker is on circulation. We exceeded the reportable quantity of SO2 as a result of the incident.
NOx: 113.0 pounds
Carbon Monoxide: 617.0 pounds
Particulate Matter: 3.7 pounds
Sulfur Dioxide: 2,232.0 pounds
Hydrogen Sulfide: 12.0 pounds
Volatile Organic Compounds (VOCs): 440.0 pounds
No LDEQ Reported

None Reported
Cause: On Friday September 13, at approximately )5:32 hrs, a courtesy call was made to the State Policy and St. Charles DEP, stating that a flash fire occurred in T-04-32, which was out of service and being cleaned.


Notes: There were no injuries from the incident. The ERT was mobilized as a precautionary measure.