Employees from two separate contractors were put at risk of exposure to the hazardous fibres, an investigation by the Health and Safety Executive of Northern Ireland (HSENI) found.
Ballymena-based Asbestos Management Services (AMS) failed to identify the risk of asbestos-containing materials in the Antrim shop on 7 January 2016.
Antrim Crown Court was told that the company had been contracted to conduct an asbestos survey and took samples before work started. However, AMS allowed the refurbishment to start before the positive sample results had been received.
HSENI inspector Kyle Carrick said: "It is essential that asbestos surveys are always conducted in a structured, methodical and systematic manner, so as to minimise the risk of exposure to asbestos from subsequent work activities."
Statistics from the Northern Ireland regulator show that in 2016, 63 people died in the country with asbestos-related disease as the primary or secondary cause.