The Health and Safety Executive (HSE) is urging public liability insurance customers to ensure their workers are adequately protected when working at height.
Its warning came after the prosecution of a Stoke-on-Trent firm following a worker fell from the first floor of a building last year and suffered life-threatening injuries.
G Baskerville of Cobridge pleaded guilty to breaching section 2(1) of the Health and Safety at Work Act 1974 and was fined £8,000, while also being made to pay £6,000 in costs.
Newcastle-under-Lyme magistrates court heard how the employee was using a power saw at Barnfields Industrial Estate in Staffordshire when he fell through the side of a building after its walls had been removed.
Guy Dale, HSE inspector, said that although there was a horizontal steel girder around the sides of the building, there were still substantial gaps and a significant risk that other workers could have fallen to the ground below.
He added: "The injured party sustained serious injuries from the fall. He had to be sedated for three weeks and spent a further three weeks in hospital. At one stage his injuries were believed to be life threatening."
Public liability insurance customers were recently told of how a lack of edge protection led to a worker falling as he was assembling a storage unit.
West Midlands Installations were fined £10,000 and £7,500 in costs for its part in the incident.