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Valero (26003), Norco

LDEQ Accident Report

Accident #133142
PDF AvailablePDF
State Police #11-04963
Accident Date2011-08-17
Report Date 2012-08-23
Follow-up Date 2011-10-14
Follow-up: Yes

Pollutants Released

Pollutant Duration Point Source Greenhouse Gas Criteria Pollutant Ozone forming chemical Amount of Release
Hydrogen Sulfide1h 10mCoker "A" drumNONONO192.0 pounds
Volatile Organic Compounds (VOCs)1h 10mCoker "A" drumNONOYES564.0 pounds
Methane1h 10mCoker "A" drumYESNOYES927.0 pounds
Ethane1h 10mCoker "A" drumNONOYES454.0 pounds

Accident Classified As: Reportable Quantity

Cause of Problem: Process Upset

Process vapors were released through a crack in the Coker "A" drum, the integrity of which is included as part of the preventative maintenance program. Therefore, this event qualifies as a reasonably unforeseeable upset. The crack occurred at an elevated altitude, and process vapors were completely dispersed near the vicinity of the Coker structure where the release occurred. The refinery estimated that 85% of the release was steam, since the product was well into the quenching portion of the process.

Discharge Preventable - No

In its follow up report, the refinery expresses a belief that the release was not reasonably preventable because the coke drums were installed in the late 1990s based on engineering data that lead to their design.

Notes/Remedial Actions

Emissions from the drum crack escaped to the atmosphere and were dispersed. The refinery shifted from 4-drum to 3-drum operation and reduced charge rates as appropriate. As of 10/14/11, the cracked drum has been repaired and returned to service. New engineering data indicates that designs that include a thicker sidewall will provide superior performance and minimize any vessel cracking. The refinery has purchased these drums, and they are on schedule for installation (replacing the old drums) in the first quarter of 2012. The refinery also has a program of routine non-destructive testing that attempts to predict potential problem areas in these drums.