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Marathon Ashland Petroleum (3165), Garyville

LDEQ Accident Report

Accident #152171
State Police #13-04960
Accident Date2013-11-06
Report Date 2013-11-12
Follow-up Date 2014-01-13
Follow-up: Yes

Pollutants Released

Pollutant Duration Point Source Greenhouse Gas Criteria Pollutant Ozone forming chemical Amount of Release
Sulfur Dioxide2hNorth Ground Flare, Heaters on Unit 243, Unit 43, and Unit 59NOYESNO15,961.8 pounds
Hydrogen Sulfide2hNorth Ground Flare, Heaters on Unit 243, Unit 43, and Unit 59NONONO5.0 pounds
NOx1h 5mNorth Ground Flare, Heaters on Unit 243, Unit 43, and Unit 59NONOYES6.0 pounds
Carbon Monoxide1h 5mNorth Ground FlareNOYESNO32.4 pounds
Volatile Organic Compounds (VOCs)1h 5mNorth Ground FlareNONOYES51.9 pounds
Methane1h 5mNorth Ground FlareYESNOYES20.5 pounds
Ethane1h 5mNorth Ground FlareNONOYES5.8 pounds
Ethylene1h 5mNorth Ground FlareNONOYES0.3 pounds
Propane1h 5mNorth Ground FlareNONOYES11.2 pounds
Propylene1h 5mNorth Ground FlareNONOYES1.8 pounds
n-Butane1h 5mNorth Ground FlareNONONO12.3 pounds
Isobutane1h 5mNorth Ground FlareNONOYES4.8 pounds
1-Butene1h 5mNorth Ground FlareNONOYES1.0 pounds
Isobutylene1h 5mNorth Ground FlareNONOYES0.5 pounds
T-butene21h 5mNorth Ground FlareNONONO0.3 pounds
Pentane1h 5mNorth Ground FlareNONOYES19.4 pounds
Carbon Dioxide1h 5mNorth Ground FlareYESNONO1.4 pounds
Nitrogen1h 5mNorth Ground FlareNONONO3.3 pounds
Highly Reactive Volatile Organic Compounds (HRVOCs)1h 5mNorth Ground FlareNONONO2.1 pounds

Accident Classified As: Reportable Quantity

Cause of Problem: Human Factors

According to the the 60-day report, the Triconix safety control system inadvertently tripped the Unit 247 Amine Unit Lean Amine Pumps. The pump shutdown caused lean amine to stop circulating to the Fuel Gas Treaters which caused high H2S-laden fuel gas to be sent to the Unit 243 Fuel Gas Drum. In addition, untreated fuel gas was sent to the Unit 43 Fuel Gas Mix Drum. The Fuel Fuel Gas Mix Drums were supplying fuel ga to 26 different process heaters and boilers with the refinery during the incident. As a result, each heater and boiler experienced an increase in SO2 emissions above the maximum allowable permitted lbs/hr rate. In addition, the Unit 247 Flash Drum overfilled into the vapor line to the Unit 210 Compressor Suction Drum, thus causing the compressor to temporarily shut down which resulted in venting to the North Ground Flare.

Discharge Preventable - Yes

The wrong version of a software system was selected. However, it should be noted that neither the software developer nor MPC was aware of the error that would occur if the wrong version of the software was selected. It was later found in the January 13th update that an internal amine circulation line was left open causing Lean Regenerator levels to drop rapidly. To prevent the unit from tripping due low leels the board operator increased Rich Amine flow rapidly. This caused the amine regenerator to become upset. At the same time a M2S analyzer, the board operator was unaware of increased H2S in the fuel gas system and not take corrective actions. A Root Cause investigation was conducted to determined the cause of the incident. Two Root cause were found. 1) A Human Performance Difficulty/ team Performance/ Misunderstood communication: the 519 operator thought the board operator meant to close the spillback instead of the lean internal circulation.2)Equipment Difficulty/ Design/ Problelm not anticipated/ Equipment environment not consider: Steam trap system malfunction due to new Fuel Gas Project tie in.

Notes/Remedial Actions

The refinery Air Monitoring Team was dispatched inside and outside the refinery fenceline. All SO2 and H2S readings were non-detect except for one 4ppm SO2 reading on Marathon Avenue in the refinery. No elevated ambient air monitoring readings from MPCs four ambient air monitoring stations were detected during the event. Operations re-started the Unit 247 lean amine pumps and re-established amine circulation to the Amine Treaters. This recirculation brought the H2S amounts in the fuel down to acceptable levels. The reportable quantity for sulfur dioxide was exceeded during the event. In addition, the permitted SO2 and the NSPS Subpart J/Ja SO2 limit for the emission sources was exceeded for multiple hours. The opacity limits for the above listed heaters and boilers were exceeded. Report was unable to be uploaded. Recommendations made for the Root cause were:1) Human Performance- Revise the Unit 19 Start up procedure with more detailing events on when to the internal lean circulation line while starting up Unit 25 with the appropriate line terminology, label lines accordingly, and retrain operators with the revision. 2) Equitment Difficulty- Evaluate the design of the existing steam tracing for the analyzer, and recommend proper mitigation.