BURNETT COUNTY, WI (WTAQ) - Fire destroyed a gymnasium Tuesday at Siren’s K-12 school building in far northwest Wisconsin.

There were no reports of injuries, and the cause remains under investigation.

Burnett County authorities were called around 10:50 a.m. Tuesday – and nearly 475 students and around 75 teachers and staff members were evacuated safely.

District Administrator Scott Johnson told WEAU-TV in Eau Claire that the blaze appears to have started in an area above a corner of the gym, where an air handling room and motors are located.

Officials said the fire spread quickly throughout the top of the gym, and the building has major smoke and water damage.

The school year was scheduled to end on Friday – and it appears that classes will not resume for now. According to the school district’s Web site, the Siren K-12 building was extensively renovated about 12 years ago, when 54,000 square feet were added. The gym was part of the older facility.