Jonathan Arnold, 49, of Castle Cary in Somerset, can now only wait and see what long-term damage has been done to him.
Mr Arnold was fitting pipework for a new central heating system at Oxford House, in Combe Down, Bath when he was exposed for five hours to high levels of blue asbestos (crocidolite).
Asbestos exposure is linked to a range of serious diseases including lung cancer, asbestosis and mesothelioma, a malignant, incurable cancer. Of the three main asbestos types, crocidolite is associated with the highest risk of developing mesothelioma.
In a prosecution brought by the Health and Safety Executive (HSE) against the building's owners, Formac Electronics Ltd, Bath Magistrates' Court heard that the airborne substance was disturbed and spread within the building during refurbishment.
The court was told that, for a five-hour period in August 2010, Mr Arnold was estimated to have been exposed to a high concentration of airborne asbestos fibres many times over the control limit.
HSE investigated the incident and found that Formac Electronics had failed to carry out a refurbishment and demolition survey to establish the presence and condition of asbestos in the building.
It also failed to provide suitable information to contractors prior to the start of the refurbishment works, which resulted in uncontrolled disturbance of the loose fill blue asbestos located within the fabric of the building.
When an HSE specialist inspector visited Oxford House under controlled conditions, loose fill blue asbestos insulation material could be clearly seen in the area where Mr Arnold had spent a long time on his hands and knees fitting pipework on 3 and 4 August 2010.
HSE inspector Helena Tinton said: "Asbestos is a potent carcinogen and is especially common in buildings constructed between 1950 and 1980. As Oxford House was built in the 1960s, Formac Electronics Ltd should have been aware of the risk of asbestos being present in the building and should have carried out an appropriate level of investigation to prevent any workers from being exposed to the substance.
"The damage to Mr Arnold's health after being exposed to such a high concentration of this potent carcinogen could be very serious and he now has to wait to find out what the long-term effects of this exposure will be."
Formac Electronics Ltd, of Oxford House, Combe Down, Bath, admitted breaching Regulation 10 of the Construction (Design and Management) Regulations 2007. It was fined £600 with £6,013.45 in costs.