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Domestic gas events and enforcement advice

Formerly OC 440/30 - Gas safety procedure and enforcement advice


This replaces OC 440/30 version 3. It outlines the main legal requirements concerning domestic gas safety, how these should be applied when dealing with relevant dutyholders and important procedures to follow. It should be read in conjunction with:


The main legal requirements for domestic gas safety are set out in:

Also relevant are:

This guidance covers how to apply fee for intervention (FFI) in domestic gas safety situations and how to follow up/deal with:

Note: Fires/explosions involving distribution pipework upstream of the consumer’s emergency control valve (ECV) are dealt with by HID (see OC 440/28).


These actions apply variously to administrative staff and inspectors at Bands 1, 2, and 3, covering initial receipt of reports, handling reports, raising investigations and special COIN recording requirements.  Appendices 1- 3 provide important technical and legal information.

Initial handling

And in all cases, with reference to the FOD gas events handling procedure.

See Appendix 2 for factors that may help with these decisions;

Closing down investigations

Investigation priorities 

Enforcement advice

Landlords and Letting Agents

Registered engineers and unregistered fitters

Competence Issues

Registered engineers

When considering competence of registered engineers, inspectors should bear in mind:

Unregistered fitters

Kitchen fitters etc

Builders and contractors

Legal issues


Appendices 1 and 2 contain further information on the legal requirements mentioned in the introduction.


Recording & Reporting

HSE publishes annual statistics of domestic gas incidents reported under RIDDOR. It is essential to ensure COIN data quality so details can be validated. For all gas fatalities:


OPSTD, MTU Sector, Utilities section.

Appendix 1: Gas incident reports [RIDDOR 2013 regulation 11(1)]

All gas incidents causing death, unconsciousness or a person(s) being taken to hospital for treatment (including: exposure to unburnt gas, fire, explosion, carbon monoxide poisoning from any cause including misuse of an appliance, suicide and failure to have appliances serviced) are reportable under RIDDOR even where there is no work related activity.  The person responsible for reporting the incident is, for incidents involving natural gas - the gas conveyor and for incidents involving liquefied petroleum gas – the gas supplier. If a fatal gas incident comes to HSE’s attention where the correct notifier cannot be identified then the local HSE office should submit the RIDDOR report in the absence of one.

The Gas Safety (Management) Regulations 1996 (GSMR, regulation 7(14)) place duties on natural gas suppliers to carry out investigations of RIDDOR regulation 11(1) carbon monoxide (CO) incidents. Similar duties are placed on gas conveyors in relation to fire and explosion incidents arising out of gas escapes from fittings in domestic premises under GSMR regulation 7(12).  OC 440/28 advises on demarcation and liaison arrangements with HID who cover incidents involving the supply pipework up to the meter.

Some reports of 'suspected' carbon monoxide incidents might later prove to be false. This may happen in the event of an unexplained death in a room with a heating appliance, someone being taken to hospital after a CO alarm has activated or fumes smelled, or following visits by engineers responding to an emergency call, as their standard procedure is to assume the worst and isolate the gas supply. Gas suppliers will usually want to be assured that CO is involved before starting a GSMR investigation and HSE should liaise with the supplier as soon as possible after receipt of the incident details to ensure any investigation is suitably progressed so the householder/tenant is not left without heating.

There is no statutory requirement for LPG suppliers to carry out investigations. Where a dutyholder is implicated, inspectors should make arrangements for technical support from Gas Safe Register, or a process safety specialist for fire/explosion incidents and LPG suppliers may assist with some investigations.

Appendix 2: Dangerous gas fittings [RIDDOR 2013 regulation 11(2)] and concerns (complaints) reports

The Gas Industry Unsafe Situations Procedure (GIUSP) provides a steer on situations which would be considered ‘dangerous’. The following information on matters causing particular concern may also help in the decision making process:

Appendix 3: Technical support for investigations

Requests to Gas Safe Register require Band 2 approval before submission;

Appendix 4: Fee for intervention (FFI) Considerations

Updated 2018-08-03