EL PASO, Texas (KTSM) — In a finalized report by the Texas Commission on Environmental Quality (TCEQ), Marathon El Paso Refinery released nearly 60 tons of sulfur dioxide after a “process upset” caused an odor that many residents across the city smelled and allegedly became sick from.

As KTSM 9 News previously reported, initial reports by the TCEQ noted that three contaminants were emitted after a fluid catalytic cracker “experienced a process upset and shut down” on Tuesday, Aug. 4.

 Stout demands accountability after emissions report in South-Central El Paso refinery ‘incident’ 

The contaminants were identified as:

Propylene – 8,897.9 pounds (emissions limit is 1.25 lbs/hr)

Sulfur dioxide – 862 pounds (emissions limit is 0.01 lbs/hr)

1,3 Butadiene – 19.1 pounds (emissions limit is 1.25 lbs/hr)

In the new finalized reports, the TCEQ reported that 23 air contaminant compounds were released from three emission points.

Here is the breakdown of the emission points, the contaminants that were released, how much of the compounds were released, and their emission limits, as provided by the TCEQ:

Tank 4118

1,3 BUTADIENE – 14.2 lbs.; 1.25 lbs/hr

2-Butene-trans – 1,703.5 lbs.; 1.25 lbs/hr

2-Methyl-1-butene – 677.2 lbs.; 1.25 lbs/hr

Cis-2-butene – 90 lbs.; 1.25 lbs/hr

Hydrogen Sulfide – 15.3 lbs.; No specific authorizations for this facility

Isobutane – 3,810.5 lbs.; 1.25 lbs/hr

Isobutene – 1,869.1 lbs.; 1.25 lbs/hr

Isopentane – 1454.1 lbs.; 1.25 lbs/hr

isopentene – 691.9 lbs.; 1.25 lbs/hr

n-butane – 869.2 lbs.; 1.25 lbs/hr

n-pentane – 159.7 lbs.; 1.25 lbs/hr

Propane – 1,911.7 lbs.; 1.25 lbs/hr

Propylene – 10,066.2 lbs.; 1.25 lbs/hr

Fluidized Catalytic Cracking Unit

Carbon Monoxide – 3,591.74 lbs.; 58.88 lbs/hr

Hydrogen cyanide – 230.02 lbs.; 8.71 lbs/hr

Nitrogen Oxides – 1,058.09 lbs.; 74.41 lbs/hr

Particulate Matter – 188.66 lbs.; 24 lbs/hr

PM10 – 179.22 lbs.; 24 lbs/hr

PM2.5 – 175.45.; 24 lbs/hr

Sulfur dioxide – 502.64 lbs.; 33.65 lbs/hr

Sulfuric acid – 7.45 lbs.; 3.96 lbs/hr

VOC (unclassified) – 23.27 lbs.; 3.57 lbs/hr

South Main Flare

Carbon Monoxide – 267.76 lbs.; 0.24 lbs/hr

Ethylene (gaseous) – 8.01lbs.; 0.43 lbs/hr

Hydrogen Sulfide – 11.74 lbs.;

Isobutane – 114.33 lbs.; 0.43 lbs/hr

n-butane – 34.5 lbs.; 0.43 lbs/hr

Nitrogen Oxides (NOx) – 39.12 lbs.; 0.43 lbs/hr

olefins – 49.91 lbs.; 0.43 lbs/hr

Pentane Plus – 59.88 lbs.; 0.43 lbs/hr

Propane – 31.12 lbs.; 0.43 lbs/hr

Propylene – 100.79 lbs.; 0.43 lbs/hr

Sulfur dioxide – 1,094.65 lbs.; 0.01 lbs/hr

According to the reports, an electrical issue caused the fluid catalytic cracker charge pumps to “trip,” resulting in a shutdown of the process unit and others.

From Aug. 4 through Aug. 7, intermittent flaring happened due to the restart of the fluid catalytic cracker. During the restart, the unit “experienced upset conditions,” leading to the overflow of contaminants, read the reports.

It was noted that flaring was not continuous during the reported incident, and most of the emissions happened on Aug. 5. The last instance of flaring happened on Aug. 7 and lasted 24 minutes, resulting in 59 pounds of sulfur dioxide being released and visible emissions for four minutes.

The fluid catalytic cracker was not in use during the restart, and to minimize emissions, diesel was added to T-4118 to “sponge” the light hydrocarbons as the process flowed from one tank to another, according to the reports.

“The majority of the emissions that contributed to the (incident) occurred in the first two hours of the event,” read the reports. “Notably, the estimated emissions in this report represent total mass emissions, in pounds, at the source (T-4118) and do not reflect ground-level concentrations at or beyond the facility’s fence line, which are relevant for assessing community exposure.”

Marathon’s Air Monitoring team observed readings through Aug. 10, and “the results indicated that air quality levels were below established community exposure guidelines,” according to the reports.

The TCEQ stated the investigation into the incident is ongoing.

This comes as families living near the refinery are seeking answers from Marathon.

 El Paso families seek answers after Marathon refinery leak 

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