power outage shutdown/startups

Valero's Meraux refinery had an emergency shutdown and subsequent startup of several units due to a power outage on Friday July 20, 2012, according to a follow up report from Louisiana DEQ. 

A downed electrical transformer is believed to be the cause of the power outage and an intensive root cause analysis is underway.  Valero's subsequent startup process resulted in high hydrogen sulfide levels in the adjacent neighborhood on Saturday night, July 21, 2012.  Some of the higher readings were at 78 ppb H2S, as measured by Valero's ambient air monitor on Ventura Drive, accesssible at this link..  The State of California's air quality limit for H2S is 30 ppb; the State of Louisiana does not have a health standard for H2S.

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photo above of shutdown during fire at Valero refinery in Meraux, LA