Flooding risk at COMAH sites - are you prepared?

Flooding is the most common and widespread natural disaster in the UK, and a number of major hazard sites have been badly affected over the years. Recent events have showed us how widespread destruction can impact local communities and businesses from flooding events. As we experience more frequent flooding across the UK, it's never been more important to make the necessary preparations to deal with the consequences of flooding in and around your COMAH site.

Under the Control of Major Accident Hazard (COMAH) Regulations 2015, flooding is recognised as both an initiator and escalation factor of major accidents. Recent flood events have put pressure on industry and emergency services and, as such, flood preparedness for major accident establishments is currently recognised by the Environment Agency, the government and industry as a high priority. COMAH sites vulnerable to flooding will need to undertake a range of assessments including carrying out topographical surveys to assess flood potential, flood Hazard and Operability (HAZOP) studies, specify appropriate and proportionate risk reduction measures and develop flood response plans and post flood recovery plans.

COMAH establishments at risk of flooding have been categorised by the UK Environment Agency according to four Flooding Major Accident Scenarios (FMAS 1-4). These range from sites directly at risk of a major accident from flooding on-site, to sites that may be indirectly affected on a local or even national scale from flooding. Operators are required to identify and characterise the flood risk to their establishments (both direct and indirect) and implement all appropriate risk reduction measures ‘so far as is reasonably practicable’.

Under COMAH Competent Authority (CCA) flood preparedness inspections, we are increasingly seeing operators of FMAS 1-3 sites now being asked to complete a flood risk assessment to ensure they are suitably prepared. New planning applicants in FMAS areas may also need to do this as part of the planning process.

A guideword-led Flood Hazard Identification Study (FHIS) can be utilised to identify all potential initiators and escalation factors for a part or all of a COMAH establishment. Correctly applied, the study can identify both natural and artificial causes of flooding on an establishment, supplemented by additional risk assessments.

The outcomes of such assessments will allow the development of flood preparedness at the site, to include:

• Information to allow sites to assess the unmitigated and mitigated flood risk and potential effects on site.
• A regular review of the suitability of existing measures in place to prevent, control and mitigate the initiation or escalation of major accidents that may be challenged or affected in the event of a flood.
• Consideration of any early warning information available for a flood event and allow development of recovery plans following an event.

If you are concerned about the risks associated with flooding in and around your site, here are 5 simple questions to ask:

• Do you understand the potential effects on and off site from flooding?
• Has a flood risk assessment been completed?
• Do you have clearly defined measures in place to prevent, control and mitigate the initiation or escalation of major accidents that may be challenged or affected in the event of flooding?
• Do you have plans in place to provide early warning?
• Do you have recovery plans in place?

Visit our Safety Advisory page to learn more about our services and how we can support you.