Agency consults on landfill sites risk assessment

The Environment Agency has issued a consultation document, Guidance on the assessment of risks from landfill sites. This guidance sets out what is required with respect to risk assessment for landfills. It is intended to provide the framework to enable landfill operators to produce a structured risk assessment that relates to the regulatory decisions that the Environment Agency must make.

It does not provide all the necessary detail to undertake individual risk assessments.
The following is a summary of the main issues raised in the guidance and upon which the Agency would particularly welcome responses:

The guidance covers risk assessments in respect of landfill gas, hydrogeological, stability, dust and accidents. The main emphasis of the guidance is on decision-making with respect to PPC permit applications.
Views are invited on the appropriateness of the scope of the guidance.

Risk Assessment Approach
(Section 2)

The guidance describes the proposed approach to risk assessment. This includes the use of a tiered approach; the source pathway receptor methodology and the use of environmental benchmarks to define what may represent an acceptable impact.
The Risk Screening approach adopted by the guidance involves basic scoring or ranking techniques to prioritise potential risks in relation to each other. This approach would place simple modelling and calculations primarily into the Simple Risk Assessment tier.

Views are invited on the approach to risk assessment in the guidance, in particular the approach to Risk Screening.

Expert Interpretation (sections 2
and 7)

The guidance stresses the need for expert interpretation. This is to ensure that any assumptions and uncertainties are clearly identified and addressed. The guidance also warns against undue reliance being placed on quantitative model results. This is to ensure that modelling is only used where the understanding of the site can support that use.
Views are invited as to the appropriateness of this emphasis and approach.

The Source, Pathways and Receptors (section 4)

The guidance describes the source of the risk, the pathways and the receptors with respect to each of the risk assessment subjects.
Views are invited as to how the guidance deals with the source, pathways and receptors.

Risk Assessment Scenarios (section 5)

The guidance considers three categories of events to describe the operations of a landfill: normal, abnormal and accidents. The guidance identifies example scenarios that can be considered in each of the risk assessment subjects.
Views are invited on this approach to categorising the potential impact of landfills through normal and abnormal occurrences and on how accidents are dealt with in the guidance.
Views are invited on the example scenarios provided.

Reporting of Human Health Impacts (section 6)

Pollution is defined as emissions that may be harmful to human health or the quality of the environment, and the risk assessment must therefore consider the potential impact on people and the environment. The guidance gives recommendations as to how a risk assessment should be reported including the potential impact on human health.
Views are invited on the reporting requirements, in particular how the risk to individual receptors should be reported and how the potential human health impact should be set out.

Decision-Making (section 7)

The guidance requires that the potential impact of the landfill is predicted for a variety of circumstances. The predicted impact is then considered together with any proposed regulatory measures and best practice operating techniques, in order to make a regulatory decision. The guidance stresses the need for expert interpretation; simple numerical pass and fail criteria cannot be used in isolation to make a decision. The Agency will make a decision based on professional judgement informed by the understanding of the landfill, the results from all the risk assessments and any consultation responses.

Views are invited on how normal, abnormal and accidents are used in the decision-making process.

The Agency adds that views are also invited on whether the guidance provides a framework for a proportionate, consistent and transparent decision based on evidence.

The document will be of interest to landfill operators, and the Environment Agency considers that it should also be of particular interest to operators and consultants involved in preparing a landfill PPC permit application. It will also be of interest to those bodies who are consultees to the PPC application process or who may wish to contribute to the decision-making process.

Terms of the consultation

Responses, requests for further copies, or queries regarding the scope or content of this paper should be made to: Jill Rooksby (Landfill Sector Coordinator), Environment Agency, Olton Court, 10 Warwick Road, Olton, Solihull, B92 7HX.
email: [email protected]
The closing date for responses is Friday 30 July 2004.

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