A GAS leak sparked a blaze at a Whitby secondary school last Thursday morning.
The fire may have been caused by someone tampering with a gas cap and occurred at Caedmon School at 8am.
Whitby fire station watch manager Chris Watson said: “It was like a large scale Bunsen burner.
“You got a really substantial, ferocious flame going up the side of the school.
“It could have been really bad but luckily we got there reasonably early.”
Gas leaking from an external pipe ignited when the school’s boiler system switched on, beside the old caretaker’s bungalow.
In addition to scorching the side of the building it also rapidly spread to guttering and the roof.
The leak was caused when a blanking cap was removed from a gas pipe leading into the school.
This resulted in a large amount of gas leaking out and North Yorkshire fire brigade has launched an investigation to discover whether the cap was simply blown off by the wind, or had been deliberately tampered with.
Mr Watson added: “It could have blown off but the cap couldn’t be found at the time, so it’s unknown whether it was deliberate.
“It was just starting to get in the roof space, but if it had been left any longer they would have had a really bad fire.”
Throughout the school are located five different shut off valves and the fire crew had to locate these before they were able to cut off the leak, meaning they were on the scene for over an hour-and-a-half.
The Gazette was unable to get a comment from North Yorkshire County Council to discover the extent of the damage to the school.