Chevron Refinery Tank Lid Fails

Wednesday, October 7, 2015 @ 04:10 PM gHale

Air monitoring in neighborhoods around Mississippi’s Chevron Pascagoula Refinery and over to south Alabama continued for a week after a tank incident.

The action followed the Sept. 27 failure of a floating lid on a nearly full tank at the refinery caused by a heavy rainstorm, which exposed a flammable gasoline blend to the air and elements.

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C Tech, a Chevron contractor, will follow the fumes, and members of the U.S. Coast Guard’s Gulf Strike Team hazardous-materials team will double check their readings.

Fumes from a 4-million-gallon fuel-storage tank at the refinery can be very dangerous. The fumes and a 4,200-gallon spill around the tank caused an increased risk of fire at the refinery.

The U.S. Coast Guard, which led the incident-response team, said the refinery was on top of the situation. The incident triggered response from federal, state and local emergency and environmental managers, along with the Chevron refinery.

The refinery cordoned off the area around the tank when it discovered the lid failure. While emptying the tank, the refinery discovered an 8-foot gash in the bottom. It said the 4,200 gallons that spilled ended up contained in the area.

It put down a flame retardant foam, said Coast Guard Mobile Sector’s Cmdr. Christopher Cederholm, who has been the on-scene coordinator for the incident, and instituted a hot area, where power was shut down and they banned anything that could create a spark.

Vapors are actually more of an explosion danger than the gasoline itself, depending on the air mixture, Cederholm said.

“You can put a match out in diesel (without fear of igniting it),” he said. “But a certain mixture at certain percentages (of a flammable substance with air) creates a danger.”

He said it’s the lower explosive limits they’re watching.

“The safety of the workforce and community remains the top priority,” said a release Oct. 2 from the Joint Information Center said. “No one has been injured and there is still no danger to the community.

“Chevron safety specialists continue air monitoring in the area. Chevron has also contracted a third party to conduct additional air monitoring in Pascagoula and throughout south Alabama. All readings in the community have been recorded without any findings” of four key hazardous chemicals, including benzene.

The Coast Guard Gulf Strike Team sent two teams Oct. 2 to conduct additional air monitoring.

“What we really want to do is ensure the validity of the response,” Cederholm said.

With the prevailing winds from the refinery blowing the fumes toward south Alabama Sept. 29, Jackson County emergency leaders got complaints from the Police and Fire Departments on Dauphin Island. Residents, uninformed about the smell, wanted to know how safe it was to breathe and what was happening.

Island residents characterized the odor as “very, very strong. ” People living in an east Pascagoula neighborhood close to the refinery said the strongest smell for them was on the day of the incident.

Workers emptied the tank Sept. 30, but the area around the tank remained partially flooded with a mix of water and the gasoline product. Refinery crews expected to finish recovering the material Oct. 2 and the incident-response team will then stand down.

The refinery will apply a microbial product to the area around the tank to minimize any remaining odor-causing vapors. The Coast Guard will be overseeing air monitoring in Pascagoula.

The state Department of Environmental Quality will oversee Chevron’s cleanup of the site.