Odorous chemicals released into air in Benicia after unit shuts down at Valero Refinery

BENICIA, Calif. (KGO) -- Residents in Benicia Saturday morning woke up to a rotten egg smell that ended up coming from the Valero Refinery. A unit shut down Friday night and crews at the refinery began moving an unnamed product that was a type of refined hydrocarbon to a holding tank. While they moved it to the tank, some of it got on the lid, releasing hydrogen sulfide into the air.

"We got the call Friday night from the refinery, a unit shut down unexpectedly, and they were going to do some flaring," said Benicia Fire Chief Josh Chadwick. "They needed to move the product from the unit that shut down to a holding unit. The ones you see on the side of the road have floating lids and some of it got on the lid."

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After the incident, Valero's ground level monitoring system showed a significant spike in hydrogen sulfide levels. Hours later, the Benicia Community Air Monitoring Program showed hydrogen sulfide levels reached nearly 100 parts per billion. The fire department said those levels can cause health concerns if exposed for a long period of time.

"The levels we were seeing in the neighborhoods are something where you wouldn't want to be in it for hours and hours and hours, but an hour or two you're going to be OK," Chadwick said.

They told residents living near the refinery to close their windows if they smelled the odor. They did not need to evacuate anyone. However, residents are concerned about what happened over the weekend.

"I knew when they kept talking about odors, it could be hydrogen sulfide," said Elizabeth Patterson, a current resident and former mayor of Benicia. "The amount, I did not know, and they hadn't reported the fence line or the ground monitoring, which had the big spikes."

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Crews at the refinery spent all day Saturday cleaning it up, and they did not finish until Sunday morning, according to the fire department. The winds were blowing away from town, but residents worry something like this can happen again when winds are blowing the other way.

"This seems to be very dangerous and there seems to be a lack of maintenance or a problem with operations, because we have had these kinds of incidents before," Patterson said.

We reached out to Valero for further comment, and we are waiting to hear back. Some in Benicia are calling for transparency.

"With Valero specifically, we have been after them in terms of reporting and getting to know more about what they are doing," Patterson said. "We also kind of like to know what their plan is for reducing the greenhouse gases, and we don't have access to that."

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