Final environmental reports released on Marathon refinery flares, emissions

EL PASO, Texas (KVIA) -- The Texas Commission on Environmental Quality released the final reports on two incidents at the Marathon Petroleum Refinery on Aug. 4-5.

In preliminary reports, the TCEQ said the refinery released three air contaminants: 1,3-butadiene, propylene and sulfur dioxide.

According to Tuesday's reports, an electrical issue led to a shutdown and restart of the conversion process used in petroleum refineries (Fluid Catalytic Cracker, or FCC).

The first incident started Aug. 4 at 7:47 p.m. and ended Aug. 7 at 3:55 p.m. The report said intermittent flaring took place due to the FCC restart. It said flaring maintained safe operation.

During this time, the refinery released 20 air contaminant compounds, including more than 3,800 pounds of carbon monoxide and 1094.65 pounds of sulfur dioxide. The carbon monoxide was released at 58.88 lbs. per hour, the report said.

The report said sulfur scavenger material was injected into the flare header to decrease sulfur dioxide emissions. The flares ensured maximum destruction and removal by maintaining proper combustion, TCEQ said.

The second incident started Aug. 4 at 8 p.m. and ended Aug. 5 at 3:30 a.m. Thirteen air contaminant compounds were released into the air, including 10,066.2 pounds of propylene.

The electrical issue led to hydrocarbons escaping through a floating roof rim seal, the report said.

To minimize emissions, diesel was added to "sponge" the hydrocarbons and redirect the flow to a different tank.

In both reports, TCEQ said the report doesn't reflect ground-level concentrations at or beyond the refinery's fence line.

Additionally, Marathon's air monitoring team monitored air quality through Aug. 10 and found that air quality levels were below established community exposure guidelines, the report said.

The reports said the investigation into the incidents are ongoing.