Crews were called to respond to a chemical spill at Liberty Power in Windsor Locks on Thursday.
Officials from Windsor Locks said some chemicals were accidentally mixed and it caused a vapor cloud over the building, which is south of Canal Bank on Elm Street.
The building was evacuated and no one was injured.
Editor's Note: An earlier version of this story said the incident took place at Ahlstrom Mills based on information provided to us by fire officials.