Walton-based W Carroll & Sons Ltd was fined £105,000 after a roofer was paralysed when he fell from a ladder in Southport while carrying a bag of building materials.
Michael Riley, 50, from Skelmersdale, now has virtually no movement below his neck and will need to use a wheelchair for the rest of his life.
W Carroll & Sons Ltd, which hired the worker as a subcontractor, was prosecuted by the Health & Safety Executive after an investigation found roofers had needed to carry heavy bags on their shoulders while they made their way down ladders.
Liverpool Crown Court heard that the company was working on a project to replace the roofs on approximately 350 properties in the Maghull and Southport area, and was using around 20 subcontractors to carry out the work.
Riley had been asked to remove cement sheets from the roof of a house on Victory Avenue in Southport, but had not been able to use the chute feeding general rubble into a skip as the sheets contained asbestos and needed to be disposed of separately.
The only way he had of getting the bags of asbestos sheets down to the ground was to hold each bag on his shoulder, with only one hand on the ladder. The bags, which weighed around ten kilograms each, could not be tied and so had to be held upright.
As he made his way down the ladder on 21 January 2011, Riley lost his balance after just a few rungs and fell backwards for several metres. He hit the back of a truck that was parked next to the scaffolding and then fell onto the ground.
Both his legs and arms were paralysed in the fall, and he suffered major internal injuries which mean he will be severely disabled for the rest of his life.
The court was told Carrolls had failed to provide a method statement or risk assessment for the work, or suitable equipment, such as a gin wheel, so that the bags could be lowered to the ground safely.
The HSE investigation also found the company had failed to change the system for removing asbestos waste following the incident, which continued to put lives in danger.
W Carroll & Sons Ltd, of Delamore Street in Walton, was fined £105,000 and ordered to pay prosecution costs of £64,600 after pleading guilty to a breach of the Health & Safety at Work etc Act 1974 on 24 January 2014.
Speaking after the hearing, HSE Inspector Alan Pojur said: "Michael has suffered major injuries that will mean he will need to use a wheelchair for the rest of his life, and he could easily have been killed because of Carrolls' failings.
"The roofers had been told not to mix the asbestos waste with the other rubble so they couldn't use the chutes. The only option they had was to carry the bulky, unsealed bags on their shoulders as they made their way down the ladders. This required them to hold the ladder with only one hand.
"It's shocking that the company failed to change its procedures even after Michael fell from the ladder, meaning other workers' lives continued to be put in danger. Falls from height are the biggest cause of death in the construction industry and it's vital firms take action to improve safety."