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Valero (26003), Norco

Releases of Propylene oxide

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

block valve
Cause: On June 13th, 2013 at approximately 12:20 pm, the reserve plant control systems alerted the control systems operator of a high scrubber temperature condition. The board operator followed procedure by monitoring the scrubber for increasing temperatures. At approximately 12:35 pm, the reserve plan control system alerted the control board operator of high-high temperature condition for the scrubber system. The board operator responded by shutting down operations in a controlled manner, after which he began field inspections of the scrubber systems and oxide systems. Upon further investigation the operator identified a block valve for the propylene oxide unloading system not fully closed, allowing propylene oxide to backflow through the low pressure vent line to the scrubber.The block valve was manually closed and propylene oxide flow to the scrubber was stopped. Initial evaluation determined that a block valve pneumatic actuator malfuntioned allowing propylene oxide to flow through the low pressure vent to the scrubber.

Followup: No

Notes: Immediate Corrective Actions: Activation of plant EOC and shutdown of oxide movement valve closure to the propylene oxide unloading block valve N2 blowback of lines to propylene oxide storage tank Maintenance request submitted for actuator and valve replacement Long Term Corrective Actions: Schedule a root cause analysis of incident to identify long term corrective actions intended to prevent re-occurrence Ensure Maintenance replaces block valve actuator Follow up with maintenance to ensure preventative maintenance is preformed on block valve Review other valves and actuators in oxide service for same issue
1,309.0 pounds