A plume of smoke and the discovery of nitrogen dioxide kept hazmat crews busy Thursday, according to a social media post by the Colorado Springs Fire Department.

Officials said that around 8:30 a.m., smoke coming from a building at 1900 W. Garden of the Gods Road forced an evacuation. A few hours later fire crews were searching for a “leak of some sort,” but had minimal information.

A social media post stated that CSFD Hazmat crews believed the plume was composed of nitrogen dioxide.

“At this facility, nitric acid is used for etching. Nitric acid decomposes into nitrogen dioxide,” the Fire Department said.

No injuries were reported as crews wrapped up their work early in the afternoon.