All classrooms at Camberley School will be back in use today after a chemical spill forced the school to close on Monday.
An old fashioned mercury thermometer broke in the science area on Friday afternoon and even though the broken parts were picked up the mercury vaporised during the weekend in the 30C heat.
The school was open for students again yesterday but the two affected classes were housed in spare classrooms despite receiving clear readings from an air assessment done by the Fire Service.
Camberley School principal Tamla Smith said they were satisfied that all classrooms were ready for use again today.
She said the quick action from the staff and agencies meant the risk to everyone's health was vastly reduced.