Dangerous Gas Fittings (Gas Industry Unsafe Situations Procedure)

OC 440/37 Version 2


This significantly revised OC provides a summary of the most recent (sixth) edition of the Gas Industry Unsafe Situations Procedure – the industry-agreed document which classifies unsafe gas fittings. The document came into effect on 1 April 2009. The OC may be helpful in understanding whether or not a gas appliance has been classified as dangerous and if it should be reported under RIDDOR 6(2). The procedure indicates different categories of danger for defective fittings along with RIDDOR reporting criteria. The guidelines include procedures for the repair, making safe or disconnection of defective fittings.


To aid operational understanding of a key gas industry document and its practical application within the industry.

Industry classification

Periodically, industry discussions are held to agree the sort of defective gas fittings which, if they cannot be rectified at the time they are seen, their installers will regard as:

Gas Safe registered engineers may only turn off or isolate appliances with the customer's permission.

In addition the guidance describes situations which may be defined as:

The Gas Industry Unsafe Situations Procedure is an industry-led initiative and the classification system used to define defective fittings is a matter for the industry. However, HSE has been consulted on the contents and made representations for the inclusion of some situations that have been highlighted by incidents.

Key changes

The sixth edition of the Gas Industry Unsafe Situations Procedure came into effect on 1 April 2009 following a period of wide consultation and includes a number of key changes. It:

The revised procedure concentrates on gas safety issues and therefore certain non-gas areas covering defects on water and electricity have been omitted. The exclusion of non-gas safety defects does not in any way seek to minimise the importance of contraventions of non-gas industry legislation/standards, but highlights the need for industry procedures to be produced for other fuels and utilities.

Please note that due to the transition to the new gas registration body (Gas Safe Register) the 5th edition of the procedure did not come into effect, so the predecessor of the 6th edition is the 4th edition.

The Industry procedure is driven by and links to requirements in the Gas Safety (Installation & Use) Regulations 1998.  It assists gas installers and others to take action when they come across defective appliances, and notify the responsible person see Regulations 26(9) and 33(3).  If the appliance/installation is considered immediately dangerous (ID) and the responsible person does not give permission for the disconnection of the appliance, the gas operative must notify the emergency service provider (for LPG the gas supplier) so that they can attend and effect disconnection.

Action by emergency service providers

Staff of the emergency service providers (ESPs) for natural gas are legally entitled to:

When called to a reported smell of fumes, a visual inspection of the gas appliances in the property will be carried out. The ESP may turn off and label any appliance that they have been called in to examine and have been unable to establish whether or not it is dangerous with a "Concern for Safety" label. The label is used when a problem is suspected but cannot be confirmed. In this situation the ESP may turn off the appliance and inform the responsible person of the need for the appliance to be checked by a Gas Safe register engineer, but they have no basis on which to disconnect the appliance. Where the ESP has been called out to an appliance where there is no clear evidence that it is dangerous, this should not be reported under RIDDOR.

Further information

A link to a free downloadable PDF copy of the Gas Industry Unsafe Situations Procedure (6th edition) can be found on the Gas Safe Register Unsafe Situations web page. A link to the Gas Safety Book is also on this page.

Any queries or marked deviations by any Gas Safe registered engineer including ESPs from the agreed guidelines should be referred to MTU Utilities Section.

Appendix - Reporting of dangerous gas fittings

Reporting of Injuries, Diseases and Dangerous Occurrences Regulations Regulation 6(2)

Guidance on reporting of dangerous gas fittings has previously been agreed with the gas industry but a review of reports received by HSE, the revision of the industry Unsafe Situations Procedure and queries received has indicated a need to revisit and clarify some issues. In particular HSE wishes to reduce the number of dangerous gas fittings reports that do not meet the legal criteria set out in  RIDDOR and improve the quality and usefulness of the reports that are sent.

What to report as a RIDDOR

Only those installations that as a result of design, construction, manner of installation, modification or servicing, pose an immediate risk to life or risk of major injury to gas users should be reported. Examples of situations that should be reported are listed below. However, it should not be regarded as an exhaustive list:

Matters of concern not reportable under RIDDOR

Some gas fittings may be found that have not been installed in accordance with the requirements of gas safety legislation in force at the time the work was carried out. Unless they are found to be dangerous, they are not reportable to HSE under RIDDOR. Nevertheless, there are some types of 'illegal' installations that call into question the competence of the original engineer and that can be reported to HSE as a complaint eg by a written note or telephone call eg Illegally installed non-room-sealed appliances in bathrooms and shower rooms (those known to have been installed after 24 November 1984), or in bedrooms (after 1 January 1996).

Additionally where appliances in rented accommodation have not been safely maintained a similar complaint report can be made. Organisations that report frequently to HSE may wish to devise a simple proforma to use.

Filling in a RIDDOR F2508G2

HSE administrative staff have received some gas safety training and they process the majority of these reports.  The person responsible for the dangerous gas fitting, known as the dutyholder, receives a letter outlining what has been reported. Matters concerning registered engineers are generally also referred to Gas Safe Register; those where non-registered engineers, builders etc are implicated are dealt with by letter where the dutyholder is previously unknown to HSE. For subsequent reports, matters are referred to an HSE Principal Inspector for a decision on whether further investigation should take place so that enforcement action such as a notice or prosecution can be considered.

The majority of the approximately 3000 forms received annually are correctly completed but a recent survey identified some areas for improvement. Only reportable incidents as defined above should be reported on Form F2508G2.

The form should be completed as comprehensively as possible. It is essential that it is made clear that the appliance/fitting has been made safe, whether by repair or disconnection; otherwise the gas administrator will have to telephone the reporting organisation to check. As much detail as possible should be provided about the person who carried out the work, although HSE recognises that this may not always be available.

The narrative box at the end of the form is very helpful in explaining the background and providing useful detail about what has been found. Please avoid acronyms, abbreviations and industry terms where they will not be familiar to a lay- person. If a gas escape is involved it is helpful to include any measurements made, eg the pressure drop.

Updated 2020-12-14