ExxonMobil's Chalmette Refinery reported a release of hydrogen sulfide and sulfur dioxide and reported the Incident Cause as a NATURAL PHENOMENON. It is unclear what triggered the flaring event. The nearby Louisiana DEQ Ch_Vista site air monitor one hour readings, listed below, recorded Hydrogen Sulfide levels in the adjacent neighborhood at 6 ppb H2S and 3 ppb H2S at 2pm and 3pm (adjust time for daylight savings time).
Valero's Meraux refinery reported startup mode with no material impact on production . The offsite effects were recorded at the nearby Ventura Drive monitor with one-hour readings for Sulfur Dioxide at 48 ppb and 120 ppb SO2 at 2pm and 3pm. This level of sulfur dioxide exceeded the EPA one-hour health standard of 75 ppb. Alarms continued to sound at the plant through the early evening, however, there were no community advisories.
|5/2/2012||.....2pm||Ch_Vista||6 ppb H2S|
|Ventura||48 ppb SO2 3 ppb H2S|
|3pm||Ch_Vista||3 ppb H2S|
|Ventura||120 ppb SO2 2 ppb H2S|
|5pm||Ch_Vista||35.7 ppb SO2|