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Shell Chemical East (26336), Norco

Releases of Hydrogen Sulfide

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

Cause: On December 6, 2012, Shell Chemical's GO-1 flared at the GO-1 Elevated Flare (EPN 1-90). The flaring was a result of an unexpected loss of power due to the trip of an Entergy breaker supplying the GO-1 unit. The GO-1 Unit trip caused a release to the atmosphere from the GO-1 Propylene Splitter Column.

Followup: Yes

Notes: GO-1 operations took the necessary steps to minimize flaring and safely return the unit to normal operating conditions and the flaring stopped. Data gathering to perform calculations and investigation are ongoing. Shell provided an amended final follow up notification on June 27, 2013. Reportable quantities for VOCs were exceeded. On December 9, 2012 the reportable quantities for Carbon Monoxide, Nitrogen Oxide, Particulate Matter, and 1,3-Butadiene were exceeded. On December 8, 2012 reportable quantities for particulate matter were exceeded. On a report dated June 27, 2013, the emissions of propylene and propane were amended.

GO-1 Elevated Flare FE-602 (EPN 1-90)
Cause: On September 24, 2012 Shell Chemical's GO-1 flared at the GO-1 Elevated Flare. Untreated RCCU dry gas was flared while isolating PV-1013, the RCCU dry gas knock out pot, where piping located at the bottom of the vessel was leaking. Equipment isolation was performed to allow access to the leaking line. Further investigation showed that the leak was due to corrosion under the insulation. The flaring at the GO-1 Elevated Flare (EPN 1-90) caused a release of hydrogen sulfide. Hydrogen sulfide also leaked from the bottom of PV-1013, the RCCU dry gas knock out pot, and flaring occurred while isolating PV-1013

Followup: Yes

Notes: Once access was provided, the line was blinded to stop the leak of untreated RCCU dry gas to the atmosphere. GO-1 operations personnel took the necessary steps to minimize flaring and eventually stop flaring, safely returning the unit to normal operating conditions. Once the unit was stabilized, untreated RCCU dry gas was routed into the fuel system and out of the flare. The leak was due to corrosion under insulation. The CUI inspection department will review service of the line and determine future inspection requirements for inspection cycle. The facility exceeded reportable quantities for sulfur dioxide (13908.15 lbs) and highly reactive volatile organic compounds (ethylene and propylene)[350 lbs]. They also exceeded permit limits for sulfur dioxide and hexane. SPOC report states material did go offsite.
31.3 pounds

Flange in OL-5 Process Unit
Cause: On August 3, 2012 Shell Chemicals OL-5 Process Unit experienced a release of pryolysis pitch from a flange while attempting to prepare a piece of equipment for a maintenance activity.

Followup: No

Notes: At the time of the release the flange was immediately closed and preparation of the equipment stopped until a new plan to complete the activity could be developed. The material was cleaned up and properly disposed. The only information given was from Shell Chemical East's Final Release Report.


Cause: On July 29, 2013, there was a release of 1,3 butadiene, benzene, and hydrogen sulfide due to a GO-1 process gas leak to the condensate system. While working with operations, personnel monitoring the fugitive emission components in the unit found the GO-1 caustic column feed pre-heater exchanger leaking process gas to the condensate system. Operations redirected the contaminated condensate to the flare system due to the condensate system flash drum venting to the atmosphere.

Followup: Yes

Notes: GO-1 operations took the necessary steps to minimize the release to the atmosphere. Operations personnel were able to complete a management of change to route the contaminated condensate to the flare. The leaking exchanger is scheduled for a metallurgy upgrade during the next GO-1 North turnaround. Upgrading the metallurgy should prevent any future leaks.

GO-1 Elevated Flare (EPN 1-90)
Cause: Shell Chemical's GO-1 Process Unit flared at the GO-1 Elevated Flare as a result of an unexpected unit upset in GO-1 caused by the receiving of off specification feed from a supplier.

Followup: Yes

Notes: GO-1 operations took the necessary steps to minimize flaring and safely return the units to normal operating conditions and the flaring stopped. No reportable quantities were exceeded.

DU-5 Unit
Cause: On September 12, 2014, Motiva's DU-5 unit received a shipment of crude oil that contained an unusually large amount of water. DU-5's normal operations removes the water from the crude and sends the water to the unit desalters. The large volume of water that was removed from the crude formed an emulsion which caused the desalter level instrumentation to malfunction. After the desalters, the water is routed to the sour water drum, but due to the instrumentation malfunction on the desalter, the water sent to the sour water drum exceeded the volume that could be pumped from the drum. The water sent to the sour water drum overflowed into the Low Pressure Flare Header. Once the water overflowed to the Low Pressure Flare Header, the liquid went to the Shell Chemical LP Utilities East Flare Pot and was combusted at the Utilities East Flare.

Followup: No


OL-5 Unit
Cause: The Shell Chemical OL-5 Unit has two pyrofrac bottoms filters. A leak in two-inch piping adjacent to one of the two pyrofrac bottoms filter caused a spill of materials. The second filter was out of service for maintenance at the time of the leak.

Followup: Yes

Notes: Operations immediately completed maintenance on the out-of-service filter and returned it back to service in order to shutdown the pyrofrac bottoms filter that was adjacent to the leak. The leak stopped once this filter was taken out of service.


Cause: On May 23, 2014, Motiva's DU-5 unit unexpectedly had the relief valve on their Debutanizer Accumulator, part of the Debutanizer Overhead System, relieve to Shell Chemical's Utilities East Elevated Flare (FE-501). The relief valve lifted as a result of an accumulation of hydrocarbons in the Debutanizer Overhead System.

Followup: Yes

Notes: Unit pressure and feed levels were safely diminished to conform to standards. 6/6/14 report states that no reportable quantities were exceeded.

GO1 Unit
Cause: The GO1 Unit flared process gas as the result of an instrument giving a faulty signal.

Followup: No

Notes: The investigation is ongoing and the report states that Shell plans to provide a follow-up.