Abbott and Mason Building and Joinery Contractors exposed an elderly resident's possessions to asbestos when carrying out renovation work at sheltered housing in West Bridgeford, Nottinghamshire.
The Mansfield firm was prosecuted by the Health and Safety Executive (HSE) after it removed asbestos insulation boards which had been used to box in pipework without taking precautions required under the Control of Asbestos Regulations 2006.
It was fined £20,000 and ordered to pay more than £5,000 costs.
A female resident at the property was exposed to asbestos, as were many of her possessions, which had to be destroyed.
The contractors also left the asbestos materials outside in the open air, risking contaminating the general public.
Both partners in the firm had received asbestos awareness training, but had failed to remove the asbestos safely.