LITTLETON - The West Metro Fire Department responded to a two-alarm fire at Chatfield High School just before noon Monday.
Welders working on the school's heating and air conditioning system caught some insulation on fire in a maintenance room inside the main building, according to firefighters.
There were 40 students attending a basketball camp at the time. Twenty-five staff members were also in the school.
All of them were able to get out of the building safely.
No one was injured.
The fire was a two-alarm event because of the size of the building, not because of the size of the fire, according to West Metro Fire.