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Shell Chemical East (26336), Norco

LDEQ Accident Report

Accident #154582
State Police #14-01206
Accident Date2014-03-17
Report Date 2014-03-19
Follow-up Date 2014-05-14
Follow-up: Yes

Pollutants Released

Pollutant Duration Point Source Greenhouse Gas Criteria Pollutant Ozone forming chemical Amount of Release
Carbon Monoxide6h 10mPrimary depropanizer and debutanizer columns in OL5 UnitNOYESNO531.0 pounds
Nitrogen Oxide6h 10mPrimary depropanizer and debutanizer columns in OL5 UnitNOYESYES97.0 pounds
Particulate Matter6h 10mPrimary depropanizer and debutanizer columns in OL5 UnitNOYESNO18.0 pounds
Volatile Organic Compounds (VOCs)6h 10mPrimary depropanizer and debutanizer columns in OL5 UnitNONOYES378.0 pounds
1,3-Butadiene6h 10mPrimary depropanizer and debutanizer columns in OL5 UnitNONOYES120.0 pounds

Accident Classified As: Reportable Quantity

Cause of Problem: Process Upset

On 3/17/2014, Shell Chemical's OL5 Unit flared process gas at the OL5 Ground Flare due to fluctuations in temperatures on the primary depropanizer and the debutanizer columns. The fluctuations in the temperatures at the primary depropanizer and debutanizer columns affected the pressure of the columns. Hydrocarbons from the depropanizer column were routed to the debutanizer column causing the pressure of the debutanizer column to rise and relieve to the OL5 Ground Flare (EPN 7-84).

Discharge Preventable - No

The incident was not preventable as the temperature fluctuations on the depropanizer and debutanizer columns were unexpected.

Notes/Remedial Actions

To minimize additional unit upset conditions and impacts, additional furnaces within the unit were put into operation. This minimized the temperature fluctuations and the OL5 Unit was safely stabilized and able to return to normal operations. No specific remedial actions have been taken or planned at this time. Values for volatile organic compounds (VOCs) includes Highly Reactive VOCs (HRVOCs), including specifically Propylene and Ethylene. These HRVOC's exceeded LADEQ RQ values, but were not reported individually.