It was reported at South Houston Green Power, which is owned by Marathon.
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While officials said air monitoring showed no chemicals, residents said these events have become a familiar part of life.
"There's been some times where you can smell it," longtime resident Cartez Green said. "This time you couldn't smell anything."
In Texas City, incidents like this have become part of the landscape.
"There was a different smell just about every day," Green said. "It was real common."
As for Sunday's event, records from the Texas Commission on Environmental Quality showed carbon monoxide and nitrogen oxides were among five air contaminant compounds identified.
TCEQ records showed another emissions event at the refinery last week that reportedly lasted nearly 23 hours and released a dozen contaminants, including nitrogen oxide and sulfur dioxide.
"We really don't think about the severity of it until after it's done," Green said.
Marathon wouldn't give any specifics about the chemicals that were burning, and only said that Sunday's incident remains under investigation.
When it comes to air monitoring, Texas City officials said firefighters carry monitoring equipment that allows crews to start testing almost immediately.
Officials said crews identify the plume, move downwind, and survey potentially affected areas near facilities and in surrounding neighborhoods.
Still, they acknowledged that monitoring provides only a snapshot in time and that conditions can change quickly depending on wind direction, temperature, and shifting chemical concentrations.
For residents like Green, he said that uncertainty is part of living alongside these industrial areas, where an alert can disappear in an hour, but the questions can linger much longer.
"It's almost like a natural thing to us that, you know, that they produce in something that smells different," Green said. "It's affecting us one way or another. It can't be a positive thing."
ABC13 followed up with Texas City officials to ask if the chemicals mentioned in the TCEQ report from Sunday's event were harmful and if they were not detected by their air quality monitoring.
Eyewitness News is waiting to hear back.