Four employees have been left living in fear for their future health after being exposed while removing soffits on a property at Chirbury Gate in Montgomery, Powys, between 16 and 17 June 2009.
An investigation by the Health & Safety Executive (HSE) found that 54-year-old Philip Leslie Davies, trading as Meadow View Windows and Conservatories, had failed to take effective measures to prevent or reduce his employees being exposed to the potentially deadly substance.
Davies admitted exposing employees to asbestos, failing to carry out a suitable and sufficient assessment, and failing to ensure adequate information, instruction and training was provided to employees.
He was charged with breaching of Regulations 5, 10(1) and 11(1)(a) of the Control of Asbestos at Work Regulations 2006.
Welshpool magistrates fined him £1,000 for each of the three charges and ordered him to pay costs of £1,615.
HSE inspector Chris Wilcox said: "Four of Mr Davies' employees were exposed to asbestos in circumstances that were wholly avoidable. They now have to live with the fear of becoming ill with a life-threatening lung disease.
"Those working in the roofline products industry must check for the presence of asbestos and be fully aware of the legal requirements for working with asbestos-containing materials."
Asbestos is the biggest single cause of work-related deaths in the UK, with an estimated 4,000 people dying every year. Information on working safely with asbestos is available at www.hse.go.uk/asbestos
The court also ordered Davies to pay a separate £15 victim surcharge, the proceeds of which will be spent on services for victims and witnesses.