Matters of Evident Concern and Potential Major Concern

OC 18/12 Version 4


This OC defines the approach to be taken by FOD staff over Matters of Evident Concern (MEC) and Matters of Potential Major Concern (MPMC). This replaces version 3, significant changes have been made throughout the document.


1. This OC contains instructions for FOD staff that require them to consider at site visits whether there are risks normally requiring immediate formal enforcement action (MECs) or other risks present that could lead to multiple fatalities or multiple causes of ill-health and, if so, take appropriate action. These high consequence events are designated as MPMCs.


2. MECs are defined as those that create a risk of serious personal injury or ill-health and which are observed (ie self-evident) or brought to the attention of FOD staff.

3. MPMCs are those which have a realistic potential to cause either multiple fatalities or multiple cases of acute or chronic ill-health. An indicative, rather than exhaustive, list of issues is given at the end of this document.

Action at premises inspected by FOD

4. As has always been required, inspectors should continue to deal immediately with any MEC that they encounter at their visits, whether or not these are related to their planned inspection or investigation. It is expected that all MECs identified should normally either result in a notice or prosecution (in line with EMM requirements) or referral to another enforcing authority (eg for general fire precautions). Inspectors are not expected to make proactive enquiries or seek information on MECs, except in Construction Division where MECs are fully incorporated into the construction programme, but they should take appropriate action to address any MECs which come to their attention (either directly or, for example, via workers' representatives).

5. In addition, FOD inspectors should proactively consider if there are hazards, which have the potential to cause multiple casualties or ill-health at all inspection visits (except visits for licensed asbestos stripping), unless specifically directed not to in other instructions. If there are such hazards, inspectors should make sufficient enquiries to form a professional judgement as to whether the associated risks are adequately controlled. If this is not the case, enforcement action should be taken in accordance with the EPS, guided by the EMM. Inspectors should take into consideration the potential for secondary consequences (eg explosion causing a building collapse), as well as that of the primary event.

6. At investigation visits, it is not expected that inspectors should actively seek out MPMCs as that would divert the focus of the investigation. However, if an inspector observes an MPMC during the course of the investigation that raises obvious concerns, they should deal with it as above. Alternatively, an inspection visit should be planned to separately address the issue(s) of MPMCs.

7. If inspectors in Construction Division identify an MEC other than at a construction site, they should address it and record in accordance with this OC eg when visiting a factory site to inspect a new extension, they encounter poorly stored flammable gases or liquids within the factory premises.  Construction inspectors are not expected to make enquiries about MPMCs at inspections beyond those directly related to construction issues.

Action by Visiting Officers - (VOs)

8. If a VO encounters an MEC during a visit, they should advise the dutyholder to stop the activity, or, if it is about to commence, not to start until a further risk assessment or reference to HSE guidance has been undertaken. If the dutyholder chooses to ignore their advice, the VO should contact an inspector by telephone to discuss the circumstances as soon as possible.

9. Where a VO suspects there is poor control of health and safety at a site where there is the potential for a high consequence event, they must raise their concerns promptly with a Band 2 inspector.


10. Dealings with either an MEC or MPMC must be recorded on COIN, except for Construction Division visiting staff who should only follow this section on recording when paragraph 7 above applies.

11. All actions taken regarding an MEC should be recorded on an IRF Other, against the relevant dutyholder. This includes Construction Division inspectors, as any MECs discussed will not be construction-related, see paragraph 7.  The Notes Detail should record;

  • The matter concerned;
  • The responsible person within the organisation seen;
  • The action taken by FOD and the action taken by the dutyholder;
  • Follow-up expected, and, when

Where formal enforcement action is not taken, the reason must be recorded. Where any follow-up is required, the issue(s), action(s) required and follow-up date(s) must be recorded using the Issues tab on the service order.

12. Where appropriate, an enforcement case should be raised by administrative staff for any Notices served and linked to the IRF Other as normal. The Issues tab need not be used when a notice is issued.

13. MPMCs should also be recorded on an IRF Other (or Case by Construction Division), with two exceptions (i) LPG Bulk tank storage and pipework, when the IRF LPG must be used, and, (ii) Legionella visits, when the IRF Legionella must be used. However, after enquiries have been made, it may be that the risks from MPMCs are being adequately managed and no further action is required. This information and the judgement and reasoning should still be recorded in the Notes Detail. Where action is required to be taken regarding an MPMC, the Notes Detail should show;

  • The matter concerned;
  • The responsible person within the organisation seen;
  • The action taken by FOD and the action taken by the dutyholder;
  • Follow-up expected, and, when (including any further MPMCs not examined at the time of the visit)

Where any follow-up is required, the issue(s), action(s) required and follow-up date for this must be recorded using the Issues tab on the service order. Where appropriate (ie formal enforcement action is taken) a COIN case should be raised by administrative staff for the above and linked to the service order as appropriate. As previously stated, there is no need to use an Issues tab where a Notice has been issued.

Indicative issues to consider

1. Fire and explosion

  • LPG storage and associated pipework (eg underground pipework; security of store and proximity of vehicles)
  • Storage of flammable liquids and solids (eg large quantities of HFLs, PU foam and other flammable solids (eg polyester resins stored within workrooms)
  • Flammable dust accumulation or collection (eg flour, wood metal powders present in workrooms; dust collection units)
  • Means of escape in cases of fire (eg blocked, locked or no exits)
  • Stoving and evaporating ovens (eg explosion relief; flammable safeguards; ventilation)

2. Health

  • Use and maintenance of cooling towers (legionella risk)
  • Metalworking fluids (significant use during machining operations)
  • Entry into confined spaces (eg silos; degreasing tanks)

3. Structural Safety

4. Pressure Vessels

  • Steam boilers and autoclaves (general condition; maintenance; written scheme of examinations.

5. Construction

  • (eg work on seriously defective scaffolding; foundations not underpinned during excavations; unsupported trench work)

6. Matters for referral to HID CEMHD

  • Matters which could impact on neighbouring COMAH site
  • See OC18/11 for full details of HID CEMHD/FOD demarcation and examples of issues which should be brought to HID CI attention.

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Updated 2020-12-11