Sylhet Welding UK and its director, Kaysor Ahmed, 42 from Walsall, have been fined after carrying out illegal gas work at restaurants across the midlands and south of England.
Mr Ahmed is not Gas Safe registered but still carried out the work himself, and employed others who were not registered over a long period.
The Health and Safety Executive (HSE) found different gas works had been carried out by the company which specialised in the manufacture and supply of industrial catering equipment.
Mr Ahmed pleaded guilty to breaching regulation 3(3) of the Gas Safety (Installation and Use) Regulations 1998 and section 37 of the Health and Safety at Work etc Act 1974, and was fined £6,600 and ordered to pay costs of £2,028. He was also banned from being a company director for two years.
Sylhet Welding UK pleaded guilty to breaching regulations 3(2) and 3(3) of the Gas Safety (Installation and Use) Regulations 1998, and was fined £6,600 and ordered to pay costs of £1,118.
Speaking after the hearing, HSE inspector Graham Tompkins said: “It is only a matter of luck that no one has been killed or seriously injured as a result of the illegal gas work carried out by this company.
“In their various incarnations, they were warned on numerous occasions that they must be Gas Safe registered in order to work with gas and gas appliances, but this was never adhered to.
“Work was carried out in restaurants across the midlands and south of England over several years. Neither Mr Ahmed nor his company was Gas Safe registered so were not qualified or competent to undertake this work.
“In some cases the installations were left in appalling conditions that put the restaurant staff and customers at real risk of possible fire or explosion.