The Health and Safety Executive (HSE) has urged landlords throughout the UK to get their properties checked over by a gas engineer every year.
It is vital that boilers are serviced regularly so they do not pose a risk to tenants.
Carbon monoxide leaks can be fatal and it is not always obvious that the deadly gas is spilling out into your home.
The HSE issued its latest gas safety warning after fining a Chester landlord £400 for failing to get her property inspected.
Chester Magistrates' Court heard that the individual had received a number of reminders about arranging a visit from a registered gas safety expert, but she failed to act on this advice.
She was first approached by the Housing Standards Officer at Cheshire West and Chester Council in May 2011 and was then contacted by the HSE on two separate occasions in July.
In September, the guilty party was given an Improvement Notice by the HSE, which gave her 21 days to arrange a gas safety inspection and provide proof that this had taken place. Again, she turned a blind eye to this.
The landlord admitted to breaches of the Gas Safety (Installation and Use) Regulations 1998 and the Health and Safety at Work etc Act 1974 when she appeared in court.
HSE inspector Martin Paren said the lady in question had ample opportunity to protect her tenants from dangerous household gases.
"Unsafe gas appliances are responsible for dozens of deaths from carbon monoxide poisoning in the UK every year. That is why it's a legal requirement for landlords to arrange checks," he remarked.
"This case should act as a warning to landlords that if they ignore the law then they may find themselves in court."
Earlier this month, the HSE urged homeowners to be wary of bogus gas engineers.
There have been a few incidents where unregistered people have carried out illegal works on people's properties.
It is important that you check a person is accredited by the Gas Safe Register before letting them start a job.