CDOIF Environmental Risk Assessments – Sustainable Solutions

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CDIOF Environmental Risk Assessment

Data Sheet for CDOIF Assessment

In the UK, CDOIF Environmental Risk Assessment refers to guidance developed by the Chemical and Downstream Oil Industries Forum (CDOIF). It provides a structured approach to assessing the environmental consequences of major accidents—particularly under

regulations such as the Control of Major Accident Hazards (COMAH). Sustainable Solutions
have had their reports vetted and accepted by the Environment Agency.

Who is Required to Use It?

The CDOIF Environmental Risk Assessment methodology is primarily intended for use by COMAH lower and upper tier establishments.

These companies fall under COMAH regulations, jointly enforced by the Health and Safety Executive (HSE) and the Environment Agency (EA).

The requirement arises when a COMAH site is preparing or updating its Safety Report—a legal document that must demonstrate how risks of major accidents are controlled, including their potential environmental impacts.

What is the CDOIF Guidance?

The CDOIF published its “Guideline for Environmental Risk Tolerability for COMAH Establishments” to standardise how environmental risk assessments (ERAs) should be performed, ensuring:

Consistent decision-making across industry and regulators
Alignment with the principles of risk-based decision-making
A clear distinction between risks that are “tolerable,” “broadly acceptable,” or “unacceptable”

What’s Involved in the Assessment?

1. Define the Environmental Receptors

Identify sensitive receptors: rivers, groundwater, soil, SSSIs (Sites of Special Scientific Interest), Natura 2000 sites, etc.
Map proximity to the site and understand potential pathways of pollution.

2. Hazard Identification

Identify potential major accident scenarios involving hazardous substances (e.g.,
tank failure, pipe rupture, fire, explosion).
Focus on those with the potential for significant environmental impact.

3. Consequence Assessment

Estimate environmental damage (to air, water, land, biodiversity) from each scenario.
Includes fate and transport modelling of pollutants (e.g., spill modelling, dispersion analysis).
Categorise the potential harm: reversible/irreversible, short/long term, localized/widespread.

4. Frequency Analysis

Use fault tree or event tree analysis to estimate the likelihood of each scenario.

5. Risk Estimation

Combine consequence and frequency to quantify risk.
Compare to established tolerability criteria (e.g., thresholds for different environmental receptors).

6. Risk Evaluation

Apply the ALARP principle (As Low As Reasonably Practicable) if risks are not in the broadly acceptable range.
Propose improvements, engineering controls, or mitigation measures as needed.

7. Documentation & Regulator Engagement

Clearly document assumptions, methodologies, and outcomes.
Submit findings to the HSE/EA as part of the COMAH Safety Report or during inspections.

If you’re working for a site that falls under COMAH or are preparing an environmental safety case, using the CDOIF guidance is effectively mandatory in practice, even if not explicitly named in legislation—it’s the accepted regulatory standard in the UK.

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