PASCAGOULA -- A chemical spill has occurred again at the Chevron Pascagoula refinery, officials confirmed Friday afternoon.
State emergency officials were notified about 11:55 p.m. Thursday of a failure at a tank, which caused up to 10,000 gallons of a hydrocarbon product to overflow.
The Mississippi Department of Environmental Quality sent an inspector to the refinery Friday to investigate the cause of the spill.
MDEQ Enforcement Chief Ernie Shirley said Chevron is calling it a "sump overflow."
"I think they called it a sump overflow," Shirley said. "They have a ditch on their property it overflowed into."
The containment ditch is lined with concrete to prevent the chemicals from seeping into the ground. Crews at Chevron will vacuum the chemicals out of the ditch and reprocess them, Shirley said.
MDEQ officials said they have not yet determined an exact amount of the chemical spill but estimated it to be no greater than 10,000 gallons.
"We just think it's a tankfull, somewhere around 10,000 gallons or less," Shirley said. "We don't have the amount, but we don't want to underestimate it."
Shirley, along with MDEQ official Nick Hatten, said the chemical appears to be benzene, a primary component of oil and other petroleum products.
Chevron representative Allison Cook said refinery teams responded and immediately contained the leak.
"The spilled material contains volatile organic compounds, VOCs," Cook said. "Refinery-safety specialists have conducted air monitoring within the refinery throughout the event response, with the results confirming there is no danger to community."
Benzene is toxic to humans. It was one of the chemicals detected in the air following the Sept. 28 accident.
Inhaling it can lead to neurological symptoms such as drowsiness, dizziness, headaches and unconsciousness, according to the U.S. Environmental Protection Agency.
Exposure to benzene in liquid and vapor form may irritate the skin, eyes and upper respiratory tract, and blisters and redness may result from contact with skin. Sources of exposure include emissions from burning oil and evaporation from gasoline stations, and in industrial solvents. These sources contribute to elevated levels of benzene in the air, which could be inhaled, according to the EPA's website.
"The refinery has notified and will continue to coordinate with all appropriate local, state and federal agencies," Cook said.
Thursday night's mishap comes on the heels of a 2 million-gallon spill after a container's lid collapsed and caused an 8-foot gash in the bottom of a tank. That spill left foul-smelling chemicals in the air for days, which could be smelled as far away as Dauphin Island, Ala.
Barbara Weckesser, who lives on Cherokee Street about a mile from the refinery, reported smelling foul chemicals in the air about noon today.
"It was similar to what we had smelled a few weeks prior," she said. "It wasn't hardly as strong, but it was similar."
She immediately contacted Mississippi Emergency Management Agency officials. A MEMA official she spoke to did not seem to be aware of the spill at the time and dispatched local law enforcement to her neighborhood, she said.
"All they told me was it might be coming from the industries in the area," Weckesser said.