This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.COMMERCE CITY, Colo. — Suncor Energy plans to restart operations Saturday morning. This after a large yellow cloud above the building prompted calls to emergency dispatch Friday afternoon. Suncor Energy said the cloud was the result of a power failure. The “significant power failure” caused “uncombusted hydrocarbon” to be released, according to the company. It is not hazardous. Suncor said one of the machines in the process of refining hydrocarbon had what it calls an “operational upset.” The malfunction caused the catalyst material to burn emitting the yellow smoke. “At approximately noon today our Commerce City refinery experienced a power failure which resulted in an operational upset. As a result of this upset a visible emission can be seen coming from the Refinery,” the company said. The company said it’s working to stabilize the plant and monitoring air quality in the area. “The emissions that you saw, it looks worse than it is. Its catalysts, sort of like fine dust off of the clay catalyst,” Suncor spokeswoman Lisha Burnett said. “It’s a scary-sounding situation, but we got no readings of sulphur dioxide on the monitors,” said Dave Biiler with the South Adams County Fire Department. The South Adams County Fire Department was dispatched to the plant at 5801 Brighton Blvd. to determine what was causing the smoke. The battalion chief earlier asked people in the area to shelter in place, and schools and businesses were also asked to shelter in place. The Denver Fire Department responded with a full hazardous materials unit to help with the Adams County hazardous materials team. Interstate 270 was closed from Interstate 70 to Interstate 76 and other roads in the area were closed as crews investigated, but they since reopened.