Businesses have been urged to make sure that any gas appliances in use are properly installed and maintained, after a firm was given a conditional discharge.
The Garage Bow Street, based in Staffordshire, pleaded guilty to breaching Section 33(1)(g) of the Health and Safety at Work Act 1974.
However, as it has now ceased trading, it was given a conditional discharge for six months with £500 in costs.
Stafford Magistrates Court heard how an inspector from the Health and Safety Executive (HSE) issued the garage with a prohibition notice after being told that its gas heater posed serious safety issues for its customers and other residents in connected buildings.
When the inspector returned to the site a month later, he recognised that a heater was still being used in the premises.
The HSE has also recently warned that anyone employed to work on gas appliances in domestic premises must be a Gas Safe registered engineer and competent in that area of work.