The Department for Infrastructure issued a new Development Management Practice Note 9b (DMPN 9b) ‘Screening projects for Environmental Impact Assessment (EIA)’ in December 2023 in order to assist planning authorities and applicants with the procedural requirements and legal principles relating to EIA screening.

The fundamental purpose of EIA is to identify the likely significant effects of a development and DMPN 9b aims to guide planning authorities through the requirements when determining whether to undertake EIA.

The DMPN 9b only deals with EIA and not other environmental regulations such as Habitat Regulations Assessments pursuant to the Conservation (Natural Habitats etc) Regulations (Northern Ireland) 1995 which should also be borne in mind by planning authorities and developers alike when considering planning applications.

This legal insight will briefly summarise the process and potential legal pitfalls surrounding the EIA screening process.


EIA is governed by the Planning (Environmental Impact Assessment) Regulations (Northern Ireland) 2017 (EIA Regulations) which sets out that planning authorities are prohibited from granting planning permission or subsequent consent for “EIA development” unless an EIA has been carried out.

This involves 1) a screening process (determining whether EIA is mandatory or required with reference to relevant thresholds and likely impacts). And 2) a scoping process (determining which environmental factors must be included in the Environmental Statement (ES) if one is required). EIA Screening is an important aspect of the planning process as the need for EIA can significantly impact on timescales for applications as well as cost. Also, it has been a popular area for legal challenges, so making the right screening decision is critical for both planning authorities and developers.

The guidance does not cover the scoping process.

EIA screening standard approach

Development, other than exempt development, that meets a description set out in Schedule 1 of the EIA Regulations is mandatory “EIA development”. Schedule 1 covers a broad range of development types from power stations to major transport and the critical issue is whether the proposed development meets, or exceeds the thresholds set out. Generally speaking, development falling within Schedule 1 is uncontroversial as usually it is well anticipated that such large-scale projects will require EIA as part of the application process. Nevertheless, the thresholds should be considered with care.

Consideration of whether a project falls into Schedule 2, particularly where thresholds are only just met and a project could be considered marginal, is more involved. The majority of legal challenges on EIA screening relate to decisions around whether a project meets the Schedule 2 thresholds and criteria so such decisions must be robust. The simplified steps to take are as follows:

Step 1: Is the development (other than exempt development) described in column one of Schedule 2 of the EIA Regulations?

  • If no, EIA is not required

  • If yes, is the proposed development located in a sensitive area?

  • If yes, go to step 2.

  • If no, does it meet any of the relevant thresholds and/or criteria in column 2 of Schedule 2?

  • If yes, go to step 2

  • If no, EIA is not required

Step 2: Taking account of the “selection criteria” in Schedule 3 (characteristics of development, location and characteristics of potential impact) is the proposed development likely to have significant effects on the environment?

  • If yes, EIA is required

  • If no, EIA is not required

A planning authority has 4 weeks to make a screening decision which can be extended upon agreement. There is no duty to consult but the screening determination should be publicly available.

The EIA Regulations only require the identification of one likely significant effect to trigger the need for EIA. Interpretation of the ‘selection criteria in Schedule 3 is probably the most complex aspect of the screening process. Impacts can be generated at any stage of the development from construction, operation to decommissioning and the new guidance recommends using a source > pathway > receptor approach to consider the effects of impacts on relevant receptors in order to make a judgement as to whether any effects are significant. A clear and methodical approach such as this should aid in taking into account the selection criteria in Schedule 3 in particular.

A particularly tricky area in the screening process is how mitigation should be taken into account. If significant environmental effects are likely, this will trigger EIA, and part of the purpose of the Environmental Statement is to assess the effectiveness of mitigation to reduce or eliminate those effects. However, in some circumstances it is permissible to take mitigation into account within the screening process and conclude that EIA is not required. The extent to which design features inherent within the development, or additional mitigation measures may be taken into account when reaching a screening determination, somewhat unhelpfully depends on the facts of each case. However a key rule flagged in the guidance is that such measures can only be considered in making a screening determination if they will lead to a significant effect being avoided or prevented. The planning authority is advised to take a precautionary approach on this issue and novel or untested mitigation proposals in particular should not be relied upon.

The use of a template is a legally acceptable way to carry out and record a screening determination, but clear reasons should be given for each step of the EIA process. Failure to give adequate reasons is a common ground of challenge in judicial review proceedings and so planning authorities must give careful consideration to reasons given for the assessment of all screening determinations (see further legal risks below).

If the applicant does not accept the determination, it has 4 weeks to seek a hearing before the Planning Appeals Commission (PAC). This is another important part of the process for the applicant in particular. There may be good reason to appeal a positive EIA screening decision given the time and cost implications of producing an ES, however this needs to be balanced against the time and resource needed to make an appeal, and the possibility that the EIA decision is upheld.

Non-standard approaches

DMPN9b sets out guidance for a limited number of circumstances when a “non-standard approach” applies to EIA screening:

  • When the developer disagrees with the planning authority determination and a hearing is held before the PAC – the PAC will issue its conclusions and the planning authority must either confirm, amend, or withdraw its previous screening determination.

  • Considering a subsequent application where an ES was previously provided by the developer – the planning authority will decide if the ES is sufficient to identify the likely significant effects. Otherwise, ‘further information’ to add to the existing ES will be requested. Timescales may be important here, for example if ecology surveys are more than two years old this might require further information.

  • Screening to determine if the proposal is unauthorised EIA development – greater precaution will apply and enforcement functions will be considered by the planning authority (see DMPN9a). The retrospective assessment of unauthorised EIA development is a complex area both practically and legally, and arguably the screening process becomes even more important in such circumstances. This is often where screening appeals arise.

  • Screening in relation to s54 applications – if the original application was EIA development, then the guidance states that the  section 54 application is EIA development. The planning authority has discretion to decide whether a fresh screening determination is required. Given that a s54 application to vary a condition could be relatively minor in terms of scope and effects, it seems somewhat counter-intuitive that it should always trigger the need for EIA. It is TLT’s view that further clarification is required on this point but ultimately it is likely to be a matter that will involve further direction from the courts.

  • When the planning authority is also the developer – appropriate administrative arrangements should be in place to ensure functional separation.

  • Where permitted development rights are involved – EIA development is excluded from the use of permitted development rights. Again this is an issue where focus on the EIA screening is important since PD rights can in some circumstances permit development of a significant scale.

  • Where DfI issues a direction that a particular development is EIA development – the Department has such power even if the development listed in Column 1 of Schedule 2 is outside a sensitive area and below the relevant thresholds.

Risks of non-compliance

The new guidance also sets out key areas of legal challenge as shown in the diagram at figure 3.1 of the DMPN (not exhaustive) such as failure to screen or publish determinations, inadequate screening and invalid determinations due to material changes in the application. Whilst this guidance will be useful in helping planning authorities avoid legal challenges, it is important for developers to be aware of the risks that objectors may seek to exploit if the EIA screening process is not properly followed for their application

Like all planning decisions, the judgement made is expected to be reasonable and rational and planning authorities should fully consider the substantive evidence of environmental risks from each development proposal. Themes and principles have emerged from legal challenges over the years including:

  • The meaning of the term ‘project’ – demolition works and construction works should be broadly interpreted.

  • That EIA should be applied with a ‘broad scope and wide purpose’ – an authority cannot ignore the need to screen simply because a project does not on first consideration closely align with the descriptions listed in Schedules 1 and 2. For example, Schedule 2(10)(b) ‘urban development projects’ regularly includes residential and housing.

  • The risk of unlawful project splitting – this is also referred to as ‘salami-slicing’ when a single development proposal is above the relevant EIA thresholds but split into smaller projects in order to avoid EIA screening. Care must be taken to properly consider cumulative effects.

In recent years, the courts have become less willing to entertain challenges against the content of an Environmental Statement as it is not the purpose of the judicial review process to step into the shoes of experts. However, the screening process remains more fertile territory for challenges since a negative screening decision that is found to be incorrect is a fundamental legal error. This is a matter that courts are generally more willing to engage with since it relates to matters of law rather than just expert judgment.

Lastly, the guidance considers transboundary effects. Significant effects can occur beyond the boundary of a proposed site via for example, air, land and water pathways. Potential engagement with authorities in the Republic of Ireland is encouraged if they are in a position to provide relevant environmental information at the screening stage.

The DMPN does not introduce any new concepts or requirements, since the principles it sets out have evolved in NI over many years, but the full guidance is a must read by way of refresher for those involved in making planning applications. The general sense from the guidance is ‘if in doubt, screen it’ so inevitably we expect planning authorities to take a broader and more precautionary approach, likely resulting in more positive EIA determinations.

Whilst an overly precautionary approach may well suit the planning authorities, the consequences for developers on what might be a marginal decision are significant. This could lead to more appeals on EIA determinations or increased application costs and timescales. The alternative risk of course is more legal challenges against negative screening decisions. Either way, the publication of this DMPN emphasises the importance of the issue, and developers should seek early legal advice in any situations where the correct course of action is unclear.

DMPN 9b can be viewed at: Development Management Practice Note 9B Environmental Impact Assessment Screening.pdf (

This publication is intended for general guidance and represents our understanding of the relevant law and practice as at December 2023. Specific advice should be sought for specific cases. For more information see our terms & conditions.

Written by

Sarah Mulholland

Sarah Mulholland

Date published

05 January 2024

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