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ExxonMobil Chemical Plant (286), Baton Rouge

Causal Factor: Instrument Failure

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

safety valves
Cause: On October 1, 2007 at approximately 2:48 PM, the LOLA T-1 tower overpressured resulting in a hydrocarbon release to the atmosphere through three of the four safety valves on the overhead of the tower. The overpressure was caused by a faulty pressure reading on the tower pressure control system. The T-1 overhead pressure instrument had been reading erratically prior to the incident and was being evaluated. During this time, the overhead pressure control valve was operated in manual to maintain a specified tower pressure. Pressure began to increase in the tower, and firing of the tower's reboiler furnace, F-402, was automatically shutdown when the pressure reached 35 psig. Furnace firing was restarted and pressue continued to rise, reaching 38.55 psig, even though the controller was using the pressure control valve in an attempt to lower tower pressure. After control was reestablished, it was determined that three of the four tower safety valves had relieved.

Followup: No

Notes: The pressure control valve on the T-1 overhead circuit was fully opened to relieve the pressure in the tower. The pressure instrument is being evaluated by instrument technicians, but at the time of the report, no cause for the erratic behavior was found. An investigation is ongoing and the appropriate follow up actions will be completed to prevent recurrence.
Benzene: 134.0 pounds
Flammable Vapor: 13,413.0 pounds

Cause: ExxonMobil had a pump that was vented to the flare due to a control system command. Unknown what caused the control system to vent the pump to the flare. Nitrogen oxide was released from the flare

Followup: No

Notes: Delay in notification because there was some confusion on ExxonMobil's part about the RQ. There have been some recent changes on the RQ for Nox for DEQ, and ExxonMobil was unsure if LSP had followed suit.
Nitrogen Oxide: 12.0 pounds

Flare #25
Cause: Due to an unknown cause, the compressor in the SACC unit failed and reduced the pressure on the system by flaring. The charge gas compressor in the Olefins unit shut down when several processing cards in the gas turbine control system failed. Four of the seven furnaces shut down immediately and gas from them were evacuated to the flare. The high rate flow caused #25 flare to smoke. The H furnace was starting up a leak developed in the convection section and uncombusted VOCs were released to air. It was believed a pinhole leak developed during steaming of furnace.


Notes: The failed cards were replaced and the unit began operation. There was a complaint about black smoke that was coming from flare for about an hour, and ongoing flare. Steam was introduced into the furnaces to displace VOCs to reduce flaring emissions. The failed cards were replaced and the unit began operation. The flaring during start up were permitted emissions.
Ethylene: 662.0 pounds
Propylene: 451.0 pounds
Butadiene: 182.0 pounds
Benzene: 167.0 pounds

Sulfur Dioxide: 1,390.0 pounds

control system on gas driven turbine driver
Cause: On 6/27/08 the charge gas compressor at the Olefins Unit shut down due to a control system failure of the gas driven turbine driver. Five furnaces automatically shut down and gas was routed to the f

Followup: no

Notes: First they cooled dow the furnace to shut down the unit. Repairs were made to the control system and restarted. Flaring occurred during startup.
: 264.0 pounds
: 274.0 pounds
: 2,658.0 pounds
: 862.0 pounds
: 1,267.0 pounds

Process gas oil line
Cause: Process gas oil spill occurred when a line was being steamed out. Steam was lined up to the process gas oil line when a gauge glass failed.

Followup: No

Notes: The gage glass failure provided an opening of about 3/4" through which 4188 lbs oil was released to soil.This stream contains approximately 0.28% polynuclear aromatic hydrocarbon. The reportable quantities were exceeded for oil to soil and for polynuclear aromatic hydroarbon. The failed gauge glass was isolated to stop the leak. An investigation is being conducted to determine the failure mechanism of the sight glass and appropriate follow up actions to prevent recurrence.
Oil: 4,188.0 pounds
Polynuclear Aromatic Hydrocarbons: 12.0 pounds


RTO unit
Cause: RTO unit atmospheric safety and associated flaring caused by loss of an electronic card and computer failure. Failure of a computer control card resulted in several control valves to fail in the closed position and the atmospheric safety valve then lifted to the flare.

Followup: No

Notes: The card was replaced with a spare and the unit operations were reduced to minimize released.
Flammable Gas: 1,000.0 pounds
Ethylene: 2,348.0 pounds
Propylene: 3,470.0 pounds
Volatile Organic Compounds (VOCs): 100.0 pounds
1,3-Butadiene: 10.0 pounds
Benzene: 10.0 pounds
Sulfur Dioxide: 500.0 pounds


Blowdown drum D-106
Cause: Earlier that morning, a TCD box, which contains computer hardware for controlling unit operations, had gone into "reset: mode and could not be restarted.

Followup: No

Notes: The box was shut down and the processor card replaced. An output card failed upon attempted restart of the box, which resulted in a steam drum safety valve lifting. Steam was sent to the Aromatic unit's blowndown drum, D-106, which has an atmospheric seal. The resultant pressure increase in D-106 caused brief venting of steam through the atmospheric seal leg. A small quantity of benzene was entrained with the steam as it vented to the atmosphere, resulting in an excess of the 10 lb reportable quantity threshold. The output card was replaced and the TCD box returned to full control. An investigation is underway to determine the root cause and prevent recurrence. This incident was not preventable because it was caused by unforseen computer hardware failure.
Benzene: 31.0 pounds

No Information Given
Cause: Instrument malfunction.

Followup: No

Notes: Instrument malfunction. May not be a real release due to freezing conditions, but weather at the time of the event was 20 degrees Fahrenheit.
Benzene: 10.0 pounds

Flare gas system
Cause: A failure of the fuel gas control valve servomechanism actuator failed due to particulate matter in the hydraulic system, causing OLA-2X gas turbine to trip and material to be released to the Site's flare gas system.

Followup: Yes

Notes: Feed was removed from five of seven furnaces and the remaining two furnaces were operating at minimal rates in order to reduce the load on the flare system and emissions to the atmosphere. The hydraulic oil filters and servos were replaced upon discovery of the foulant. The hydraulic oil system was drained, cleaned, and charged with fresh oil in December 2012 to remove a suspected contaminate and particulates. ExxonMobil is conducting additional laboratory analysis of the lube oil at our lubes and specialities lab to determine if additional steps are needed to help prevent recurrence. In addition, improved filtration has been installed. A citizen complaint was recorded and given LDEQ incident number 144543. The complaint cites "Exxon release causing terrible odors, making the caller sick." The LDEQ report references this report, incident 144539 for information on the release. The reportable quantities for VOC, benzene, ethylene, propylene, isoprene, 1,3-butadiene, sulfur dioxide, and nitrogen oxide were exceeded as a result of this event.
Volatile Organic Compounds (VOCs): 12,208.0 pounds
Benzene: 819.0 pounds
Ethylene: 3,572.0 pounds
Propylene: 1,423.0 pounds
Isoprene: 399.0 pounds
Nitrogen Oxide: 3,938.0 pounds
Sulfur Dioxide: 28,988.0 pounds
1,3-Butadiene: 924.0 pounds


No Information Given
Cause: On August 5 at approximately 2:17 PM, the ECLA-W cracker compressor shut down due to an unplanned processor card failure in the compressor control circuit. Feed was immediately isolated from all furnaces serviced by the compressor to reduce flaring until the compressor was restarted. This incident is under investigation to determine which component(s) of the processor card failed.

Followup: No

Notes: Feed was isolated from all furnaces serviced by the compressor to reduce flaring until the compressor was restarted. This incident is under investigation to determine which component(s) of the processor card failed and to provide mitigating actions to prevent this incident from occurring in the future.
Ethylene: 213.0 pounds

WILA unit
Cause: ON June 25, 2013, the Baton Rouge Chemical Plant WILA unit experienced a series of intermittent PV vent liftings on TK 8 & 9. This event was due to level instrument malfunction on a water/butadiene separation drum during startup of the BELA-5 unit caustic scrubber system. As a result, butadiene was sent to the WILA unit. The butadiene vaporized in TK 8 & 9 causing elevated pressures, resulting in the PV vent liftings. The source of butadiene was immediately stopped and the WILA feed line was purged of butadiene to the flare system. Approximately 33 pounds of benzene and 2100 pounds of 1,3-butadiene were released as a result of the event.

Followup: No

Notes: The source of butadiene was stopped and the WILA feed line was purged of butadiene to the flare system. Repaired level instrument/control valve. Repaired site glass to restore visibility and enable confirmation of level instrument reading. Conducted refresher training for the process organization on improved alarm response to low level readings.
1,3-Butadiene: 2,100.0 pounds
Benzene: 33.0 pounds

Cause: On May 26, 2013 smoke was discovered coming from the stack of the steam cracking furnace KGF-01 at SACC. Upon investigation of the smoking, flooding conditions on the furnace were discovered and immediately mitigated. After further evaluation, it was determined that the furnace began experiencing flooding conditions during routine operation on May 25, 2013 at 3:23 am. Furnace flooding occurs when there is more fuel gas inside of the furnace than can be completely combusted. The uncombusted fuel gas released resulted in RQ exceedences for ethylene and flammable vapor. An investigation is underway to determine the root cause. An oxygen analyzer false reading caused the furnace to go into a flooded condition.

Followup: Yes

Notes: Upon discovery, the furnace flooding conditions were mitigated. An oxygen analyzer false reading caused the furnace to go into a flooded condition. Conflicting analyzer readings caused the unit operator to make adjustments that extended the event duration and increased the degree of flooding to the point of generating smoke in the stack. Immediately upon discovering smoke from the stack, the furnace operation was corrected. Improvements to furnace controls and operator training are being implemented to prevent recurrence. Final investigation results indicate that the furnace flooding conditions were a result of an oxygen analyzer false reading. The follow up letter dated August 29 indicates a false reading, but the document scanned into EDMS only included one document and no additional information.
Ethylene: 883.0 pounds
Flammable Vapor: 54,000.0 pounds


Cause: On May 21, the Baton Rouge Chemical Plant experienced a turbine trip at the OLA-2X unit. The material released was sent to the site flare gas system. After further investigation, it was determined that this event was due to the failure of the fuel gas control valve servomechanism actuator. The servomechanism actuator failed due to particulate matter build up in the hydraulic oil system.

Followup: No

Notes: Immediate remedial action was to reduce unit feed rates to help minimize emissions. The hydraulic oil filters and servomechanism actuators were replaced prior to restarting the machine.
Ethylene: 3,709.0 pounds
Propylene: 1,477.0 pounds
Benzene: 850.0 pounds
Isoprene: 414.0 pounds
1,3-Butadiene: 959.0 pounds
Sulfur Dioxide: 30,097.0 pounds
Nitrogen Oxide: 4,089.0 pounds
Volatile Organic Compounds (VOCs): 5,267.0 pounds