The two workers had been investigating a leak from the roof at Karro Foods’ Malton site in Yorkshire when the incident occurred on 13 April 2016, Leeds Magistrates’ Court heard.
Unknown to the pair, the roof had several rooflights. The workers were walking closely together and both fell 4m through the rooflight which gave way due to their weight.
One worker suffered four fractured ribs, a punctured lung, and muscular bruises to his outer right thigh.
The other suffered a fractured skull, muscular injuries to his right leg and injuries inside his ear. He has ongoing problems with balance, memory and mental health.
An investigation by HSE found the roof was made of asbestos cement and had several rooflights along it which were not visible due to a build-up of moss and dirt. Employees had also not been made aware of them.
Karro Foods Ltd of Norton Grove Industrial Estate, Malton, Yorkshire pleaded guilty to breaching Section 2 (1) of the Health and Safety at Work Act 1974. The company was fined £1,866,000 plus £8,019 in costs.
Investigating HSE inspector Mark Slater said after the hearing on 22 March: “This was a wholly avoidable incident, caused by the failure of the company to provide adequate controls against the risks arising from working at height.
“Consideration of roof fragility and rooflights, visible or not, should be made, especially on older buildings.”