Yellow smoke over Denver and Commerce City “not hazardous,” Suncor says, but the state is still investigating

(Andrew Kenney/Denverite)

A plume of yellow and black smoke poured out of a Suncor refinery north of Denver on Friday around noon. People in the area were told to shelter in place and schools were locked down, but those orders were lifted a little after 2:10 p.m., according to Capt. Greg Pixley of the Denver Fire Department.

Suncor Energy Inc. and emergency responders have been monitoring the air for sulfur dioxide, which can have negative effects on respiratory health. Sulfur dioxide was not detected at ground level, according to Suncor spokesperson Lisha Burnett. The cloud largely consisted of a “clay-like material” used in the refinery, she said.

No injuries have been reported, Pixley said, and “as of now there’s no concern to the community.” Authorities responded with an “overabundance of caution,” to ensure they stayed ahead of any potential dangers, according to Deputy Chief Dave Bierwiler of the South Adams County Fire Department.

The emission was “not hazardous,” Burnett said. Symptoms to watch for from sulfur dioxide include shortness of breath, wheezing and chest tightness, especially among children, the elderly and people with asthma.

The Colorado Department of Public Health and Environment, however, is still investigating the incident, and “does not yet have enough information about the release to determine if it was hazardous,” according to a news release. Still, CDPHE found the smoke “does not appear to pose any immediate risk to the surrounding community.”

The cause of the cloud:

A power failure around noon resulted in an “operational upset,” at Suncor’s refinery in Commerce City. (The company is based in Alberta, Canada.) “As a result of this upset a visible emission can be seen coming from the Refinery,” Suncor spokeswoman Nicole Fisher wrote in an email.

“We are working to safely stabilize the plant following the power failure … The regulators have been notified and we have initiated air monitoring in and around the refinery and neighbouring community.”

In response, emergency officials used reverse-911 to tell people within two miles to shelter in place.

Ben Markus of CPR reported that the plume transitioned within about 20 minutes from yellow to black in color. Michelle Halstead, a Commerce City spokesperson who was driving past the site at 1:20 p.m., said she could not see the yellow cloud.

I-270 was shut down from I-70 to I-76, but it was reopened as of 1:20 p.m.

A similar incident was reported in 2012. Sean Ford, the mayor of Commerce City, said this type of incident doesn’t happen very often. Speaking by phone just before 2:30 p.m., he said he could not go into much detail because he was still learning about the incident.

“Suncor’s always been a great employer in Commerce City. We want them to be safe, to ensure our residents that they’re safe — and we want to make sure that whatever activity, regardless of the company, that our residents are safe,” he said.

Andrew Kenney

Author: Andrew Kenney

Andrew Kenney writes about public spaces, Denver phenomena and whatever else. He previously worked for six years as a reporter at The News & Observer in Raleigh, N.C. His most prized possession is his collection of bizarre voicemail. Leave him one at 303-502-2803, or email