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Louisiana Refinery Accident Database

Motiva Enterprises (1406), Norco

LDEQ Accident Report

Pollutants Released

Accident Classified As: Reportable Quantity

Cause of Problem: Weather

Heavy rains caused excessive rainwater weight on roof of tank F-493, causing naphtha to leak out via the roof drains into diked area around the tank. Tank F-509, which shares the containment dike with F-493, had to have its tank dike valve opened to prevent flooding, causing surface water to contact area around F-493 and then escape to the effluent conveyance system. Facility was forced to bypass the stormwater impoundment basin to avoid flooding of the site and the released naphtha then migrated offsite through outfall 006. DEQ interview form states area could not be entered on the first day because of high benzene levels.

Discharge Preventable - Yes

The release initially contained in tank F-493's dike was not preventable, as the design of the roof drain provided insufficient hydraulic flow for rainwater collected on the tank's roof. Release involving the migration of 15 gallons of Naphtha off site through Outfall 006 was preventable.

Notes/Remedial Actions

Operations immediately closed the roof drain valve of tank F-493, notified the Norco Site Supervisor, and called out additional personnel to begin containment and clean up. Fence line monitoring was initiated to monitor potential off-site impacts upon identification of material migration off-site. Vacuum trucks and absorbent pads were utilized to recover all standing liquid hydrocarbon following the release. Used waste pads were packaged in 55-gallon drums and disposed of off-site at the Phillips Reclamation Facility. Liquid phase material was recovered via the facility's slop oil system. To prevent recurrence, the roof drain will be up-sized during the next scheduled turnaround to 6" from the current 4" configuration to ensure unhindered migration of rainwater from the roof to the dike area. Tank dike draining procedures were reinforced with operations via shift meetings. The 15 gallons of Naphtha that migrated off site through Outfall 006 was collected in the stilling basin upstream of the St. Charles Parish Bayou Trepagnier Pump Station via absorbent material and pads which were once again packaged in 55-gallon drums and disposed of off-site at Phillips Reclamation Facility. Personnel involved in the incident regarding the migration of 15 gallons of Naphtha off site were led through discussions to avoid future recurrence. The findings of the investigation were dispersed throughout operations via shift meetings and Shift Core Team Leaders.