Black smoke billowed from the Suncor Energy oil refinery in Commerce City on Tuesday afternoon as the facility shut down one of its plants due to a possible electrical issue.
Gusts of smoke from the Plant 2 main flare were visible for miles, leading the Colorado Department of Public Health and Environment to send an inspector to the site and the company to issue one of its public notifications about refinery activity.
On Wednesday, Suncor filed a malfunction report with the state health department that listed the pollutants that it released in excess of the allowable amounts in its air-pollution permit. The company also said the malfunction was ongoing, and that it continued to release higher levels of carbon monoxide and hydrogen sulfide, which also created more sulfur dioxide, according to the report.
The company also exceeded the amount of black smoke that it is allowed to spew into the sky, according to the report. The company’s Title V air permit limits visible smoke to six minutes per hour.
Kate Malloy, a spokeswoman for the state Air Pollution Control Division, said strong winds on Tuesday and Wednesday pushed the pollutants higher into the air and lessened the amount that people on the ground near the refinery would breathe.
Suncor informed on Tuesday the state’s Air Pollution Control Division of the problem and reported that the smoke potentially violated the terms of the company’s air-pollution permit, Malloy said.
The company also reported that it may have released too much carbon monoxide from its Plant 2 fluidized catalytic cracking unit, one of the main pieces of equipment used to convert crude oil into gasoline, she said.
Air-quality monitors around the refinery did not record elevated amounts of sulfur dioxide, carbon monoxide or particulate matter, Malloy said. Other toxics such as benzene, toluene, ethylene oxide and xylene also were below federal health standards.
However, ambient air concentrations at those monitors are different from flare emissions, which are released at higher altitudes than the monitors, which are placed along the borders of the Suncor property.
“We will continue monitoring the situation and air pollution levels in the area,” Malloy said.
Suncor did not respond to an email inquiry from The Denver Post.
The company’s notification, sent via email and phone calls to people who have subscribed to alerts, said increased smoke from the flare may be visible for several days as the plant undergoes maintenance that requires workers to shut down and restart equipment.
The refinery’s Plants 1 and 3 are also down for planned maintenance, Malloy said.
The refinery uses flaring to burn off excess gases to manage pressure within the equipment. When flaring occurs, passersby can see flames coming from smokestacks. However, black smoke is unusual.
“Flaring is a standard safety practice that allows for the controlled burning of process gases to safely manage pressure,” Suncor’s notification said. “We continuously monitor the air around our operations and provide air quality data and information with our neighbors and the public through near real-time community and fenceline monitoring systems.”
