Emergency services were called to Dunfermline High School following a chemical scare in the building on Monday night.
Firefighters, police and ambulances were sent to the Fife secondary after reports of an “unfamiliar” smell in one of the hallways just after 5pm.
Specialist fire and rescue teams were called out amid fears the substance may have been harmful with “precautionary” gas monitoring equipment put to use.
However the chemical was found to be non-hazardous and there was no danger to the public.
The Scottish Fire and Rescue Service (SFRS) said they were called after receiving a report of an unusual smell at the school.
Four appliances – two from Dunfermline, one from Lochgelly, and a detection, identification and monitoring vehicle from Edinburgh’s McDonald Road – were sent to the school.
A fire and rescue spokeswoman said: “Crews dealt with an unknown chemical. Precautionary gas monitoring equipment was in use. The stop message came back at 7.52pm.”
Specialists could not find traces of any harmful vapours or gas.
A police spokeswoman said the force was asked to attend at 5.10pm.
She added: “There was a chemical smell. We were called in case we were needed.”
Fife Council service manager Neil Finnie said: “Due to an unfamiliar smell in the stairwell at the end of the building, as a precautionary measure, the emergency services were called out.
“This is unlikely to have any impact on the operation of the school tomorrow.”