Environmental reports detail what gases caused strong odor from Marathon refinery

EL PASO, Texas (KVIA) -- Two environmental quality reports said the Marathon El Paso refinery released harmful gasses in South-Central on Tuesday and Wednesday. One of the reports noted one of the gases released for 24 hours.

Tuesday night, residents near the refinery noticed a strong gas odor. District 2 City Representative Josh Acevedo confirmed the smell came from the Marathon refinery. He said air monitoring in the area didn't detect any readings indicating health risks.

The Texas Commission on Environmental Quality's reports from Wednesday said the Marathon refinery released three air contaminant compounds: 1,3-butadiene, propylene and sulfur dioxide.

According to both reports, the conversion process used in petroleum refineries (Fluid Catalytic Cracker, or FCC) had a process upset, which shut down and resulted in emissions to flare. As a response, the FCC and other process units shut down.

1,3-butadiene

The incident report said an estimated 19.1 pounds of 1,3-butadiene went into the air for two hours and 13 minutes Tuesday from 7:10-9:23 p.m.

According to the U.S. Department of Labor, 1,3-butadiene produces through the processing of petroleum and is mainly used to make synthetic rubber. It's also found in small amounts of plastics and fuel.

It's described to be a colorless gas with a mild gasoline-like odor. The U.S. Department of labor said low exposure may irritate the eyes, throat nose and lungs. With skin exposure, the gas may cause frostbite, the department said. Higher exposure may cause decreased blood pressure, headache, decreased pulse and fainting.

The Labor Department said it's common to be exposed to the gas in the petroleum refining industry. Others can be exposed through polluted air near chemical, plastic or rubber facilities.

Propylene

According to the incident report, an estimated 8897.9 pounds of propylene went into the air for two hours and 13 minutes Tuesday from 7:10-9:23 p.m.

Propylene is another colorless gas with a petroleum-like odor, according to the National Oceanic and Atmospheric Administration CAMEO Chemicals database.

The database said when it's moderately concentrated in the air, it can cause dizziness, drowsiness and unconsciousness.

Sulfur dioxide

The Texas Commission on Environmental Quality's second report said the refinery released sulfur dioxide into the air for 24 hours starting Tuesday at 7:47 p.m. An estimated 862 pounds went out, the report said.

Like the other gases released, sulfur dioxide is colorless with a strong odor. The National Park Service said the gas can threaten human and animal health. Fossil fuel combustion is one of the main sources of sulfur dioxide emissions.

NPS said sulfur dioxide irritates the skin, eyes, nose throat and lungs. The gas can also reach with other chemicals in the air and change into a particle that can get into the lugs.

Several South-Central El Paso residents told ABC-7 they felt their eyes burn Tuesday night while the gasses emitted into the air.

"I was coughing, I felt a little dizzy and nauseous," Katrina Osborn said.

On social media, residents expressed confusion about the smells, as they didn't know what they were in the moment. One resident said she started to reconsider moving to the area.

"I was considering buying a house around here, and that is one of the reasons why I'm having second thoughts about looking for homes around here. Because I don't know what we're exposed to," Grace Torres said.

Wednesday, ABC-7 reached out to the Marathon refinery, and a spokesperson said teams addressed the situation. Again, air monitoring deployed and reportedly didn't detect any readings that indicate health risks.