Black smoke is rising from the roof of the downtown Sheraton, but it’s not a fire

The Denver Fire Department responded to the downtown Sheraton Hotel after black smoke began to rise from the roof on Thursday morning, but it turned out to be an emission from a generator.

Denver Fire spokesman Greg Pixley says he’s unsure of the circumstances at the moment because firefighters are on an unmonitored radio channel used to communicate in high-rise buildings.

He did say that the department suspects that the hotel is either testing a generator or a generator kicked on. Generators are diesel-powered and produce black smoke, especially when they first start up and don’t run as efficiently as they should, he said.

Update: Firefighters have confirmed that the smoke was caused by a generator. There is no fire or emergency.

According to the Denver Post’s Jesse Paul, there were no visible flames.