The abandoned Old Sugar Mill factory near Longmont caught fire just after midnight Tuesday, according to the Boulder County Sheriff's Office.Due to hazardous materials and weather conditions, the Boulder County Sheriff's Office said firefighters will not actively fight the fire, and instead let it burn throughout the night. The Boulder County Sheriff's Office and Longmont Fire Department said it would stay on scene to monitor the fire. There is no danger to the public though, the Boulder County Sheriff's Office reassured. Just remain outside the area controlled by Longmont FD and the Boulder County Sheriffs' Office. The cause of the fire is under investigation. Abandoned Sugar Mill factory burning since midnight TuesdayThis property has seen three fires since 2017, the most recent was last August. Firefighters took the same approach to that fire, letting it burn for more than 24 hours. Prior to that, there was a fire on the property Dec. 9, 2020 and Dec. 25, 2017.The property has been abandoned since 1977, the Denver Post reported. The sugar factory was built in 1903 and named the Great Western Sugar Co. ...read more read less