Carbon monoxide has no smell. The person who fitted your boiler last Tuesday might not have had a qualification either. The combination is lethal.

Across the island, prosecutions for illegal gas work are rising. Seventeen cases have moved through the courts in a recent surge, and that number represents only the cowboys who got caught. The ones who did not get caught are still knocking on doors, quoting low, and leaving behind installations that fail quietly in the night.

This is not a niche problem for people who hire strangers off lamp posts. Unregistered gas work happens in newly renovated kitchens, in rented houses, in homes where a friend of a friend did it cheap. The customer often has no idea anything is wrong. That is the whole problem.

What the Law Actually Requires

In the Republic, anyone carrying out gas installation, commissioning, maintenance or repair work must be registered with Register of Gas Installers of Ireland (RGII). In Northern Ireland, registration with the Gas Safe Register is the legal requirement. These are not optional quality marks. Working outside them is a criminal offence.

The register exists because gas work done badly kills. Carbon monoxide poisoning, gas explosions and fires traced back to substandard installations are not theoretical outcomes. They are the reason the registration system exists in the first place.

A registered engineer carries a current ID card. That card has a unique licence number, an expiry date, and a list of the specific types of gas work they are qualified to do. A boiler installer is not automatically qualified to work on a gas cooker or a commercial kitchen setup. The categories are specific, and so is the card.

The Red Flags That Actually Matter

No ID card produced without prompting. A legitimate engineer expects you to ask. They carry the card ready. If someone shows up to work on your gas appliance and waits for you to forget to ask, that is the first flag.

Quoted price that is significantly below market rate. Gas work has a floor price set by the time it takes to do it properly. Safety checks, commissioning records, leak tests, compliance certificates. Skip those steps and the price drops sharply. If the quote sounds too good, ask yourself what has been left out.

No mention of a completion certificate. After any gas installation or significant work, you are entitled to documentation. A registered engineer issues a certificate of conformance or a landlord gas safety record depending on the work done. If the trader says "I don't bother with paperwork" or charges extra for it, stop the conversation.

Verbal reassurances instead of verifiable credentials. "I've been doing this for twenty years" is not a registration number. "Everyone uses me around here" is not a qualification. The only thing that matters is a current, valid ID card you can check against the register online.

Pressure to start immediately. Legitimate engineers are busy. They quote, they schedule, they arrive on the agreed date. A trader who pushes hard for same-day work and cash payment before you have had time to think is not operating with a registration to lose.

No fixed business address or professional contact details. A mobile number on a handwritten card is not grounds for automatic suspicion on its own. But combined with any other flag on this list, it matters. Registered engineers are traceable. That traceability is the point.

How to Verify Before Anyone Touches Your Appliances

Go directly to the RGII website if you are in the Republic, or the Gas Safe Register website if you are in Northern Ireland. Both allow you to search by registration number or by name. Do this before work starts, not after.

Ask to photograph the ID card. A confident, registered engineer will not object. The card has a QR code on current versions that links directly to the online register. Scan it. If the page that loads does not match the person standing in front of you, do not let them start work.

For landlords, this is not optional housekeeping. Unqualified gas engineers working on rental properties represent a direct legal exposure. A gas-related incident in a property where you cannot produce a valid safety certificate from a registered engineer creates a liability that no landlord wants to face. Annual gas safety checks by a registered engineer are a legal requirement for landlords in both jurisdictions.

What to Do If You Suspect Illegal Work Has Already Been Done

First, stop using the appliance if you have any doubt about safety. This is not overcaution. An incorrectly installed or commissioned gas appliance can fail slowly or it can fail all at once.

Call a registered engineer and ask for a full inspection. Tell them what you know about who did the previous work. They will check for correct installation, proper sealing, adequate ventilation, and accurate commissioning. Get the results in writing.

Report the trader. In the Republic, contact RGII directly. In Northern Ireland, Gas Safe Register has a reporting mechanism. You can also report to the Health and Safety Authority in the Republic. These reports matter. The prosecutions happening now came from someone making a call.

If you believe there is an immediate danger, contact Gas Networks Ireland in the Republic on 1800 20 50 50, or call your gas supplier's emergency line in Northern Ireland. They respond 24 hours.

The Landlord Question Nobody Wants to Answer

A significant portion of illegal gas work happens in rental properties. The economics are straightforward and grim: an unregistered trader charges less, the landlord saves money, and the tenant lives with the consequences. Some landlords know exactly what they are doing. Others genuinely believe the person they hired was qualified because they said they were qualified.

Neither position protects you legally or morally when something goes wrong. If you manage rental properties and cannot produce a valid gas safety certificate from a currently registered engineer for every gas appliance on the premises, fix that today. Not next month.

The traders doing this work are counting on customers not checking. Seventeen prosecutions suggests the tolerance for that gamble is running out.

Check the card. Verify the number. Get the certificate. It takes ten minutes and it is the only thing standing between a safe home and a problem you cannot fix after the fact.