Leeds Crown Court heard how on 26 August 2014, the worker was asked to remove fall bags from the first floor of Sandal Endowed Primary School in Wakefield.
The bags were too bulky to fit safely down the stairs so he took the bags to the roof and proceeded to throw them over the edge.
One of the bags became caught on the edge protection, dislodging it and taking both him and the edge protection over the edge.
The employee fell and landed on the unprotected end of a scaffolding pole resulting in broken ribs and internal injuries and later removal of part of his bowel due to infection
An HSE investigation found that George Hurst & Sons Ltd failed to implement the British Standard for edge protection.
George Hurst & Sons Limited of Swinton, pleaded guilty to safety breaches and as the company has gone into administration was fined £1.
After the hearing, HSE inspector Yolande Burns commented: “This accident would not have happened if the standard had been met. The breaches were ongoing for a period and many other employees were exposed to the risk of falling over the edge of the building.
“Falls from height remain one of the most common causes of work related injuries in this country and the risks associated with working at height are well known.”