Assessing Potential Environmental Impacts and Material Contravention of Non‑Zoning Objectives: Commentary on Oxigen Environmental Unlimited Company v An Coimisiún Pleanála [2025] IEHC 632

Assessing Potential Environmental Impacts and Material Contravention of Non‑Zoning Objectives: Commentary on Oxigen Environmental Unlimited Company v An Coimisiún Pleanála [2025] IEHC 632

1. Introduction

This commentary examines the judgment of Humphreys J in Oxigen Environmental Unlimited Company v An Coimisiún Pleanála [2025] IEHC 632, a decision of the High Court of Ireland (Planning & Environment List) delivered on 19 November 2025.

The case arose from a refusal of planning permission for a large mechanical biological treatment (MBT) waste facility in rural County Louth. The proposed facility, handling up to 90,000 tonnes per annum of municipal solid waste, would operate on a 24-hour basis and was to be located on an unserviced “greenfield” rural site approximately 70 metres from the nearest existing dwelling and in the vicinity of several others.

Louth County Council refused permission. On appeal, An Coimisiún Pleanála (formerly An Bord Pleanála, “the Commission”) refused permission on three grounds, citing:

  • material contravention of the development plan’s rural policy objectives and unsuitability of the unserviced rural location (Reason 1);
  • potential serious injury to residential amenity due to air quality and noise impacts (Reason 2); and
  • potential adverse impacts on groundwater and the hydrological regime, with consequential risk to water supply, public health and “Good Water Status” under the Water Framework Directive (Reason 3).

Oxigen brought judicial review proceedings seeking, principally, to quash Reasons 2 and 3, to obtain declaratory relief concerning the zoning status of the lands, and alternatively to quash and remit the Commission’s decision. The Court dismissed the proceedings in their entirety.

The judgment is significant for several reasons:

  • it re‑emphasises the narrow scope of judicial review over planning “evaluative judgments” and the high bar for alleging irrationality;
  • it clarifies that “potential” and unmitigated impacts are not only permissible but required considerations under the EIA Directive;
  • it confirms that planning authorities are not bound to accept a developer’s EIAR conclusions, even if uncontradicted by contrary expert evidence;
  • it underscores a strict approach to late evidence in the expedited planning judicial review regime; and
  • it elaborates the law on material contravention, confirming that it can arise from non‑zoning objectives and rejecting a narrow “fundamental-undermining” threshold for materiality.

2. Summary of the Judgment

2.1 The Development and Decision Under Challenge

The proposed development at Ardee Road, Carnabreagh, Dundalk, Co. Louth, comprised a waste recovery and recycling facility on a 2.6ha rural site including:

  • a large processing building (approx. 9,263 m², height 13.85m);
  • ancillary administration building;
  • access road off the L3168, weighbridges, ESB substation, fuel storage;
  • car and bicycle parking, security infrastructure, and landscaping; and
  • a requirement for an Industrial Emissions licence from the EPA.

The facility would accept municipal solid waste by HGV from 07.00 to 00.00 Monday–Saturday, with its internal processes operating on a 24-hour basis. It was in an unserviced rural area with nearby houses (three immediately adjacent and approximately 12 in the wider vicinity).

Louth County Council refused permission for five reasons, including overdevelopment of a constrained rural site, visual impact and harm to residential amenity. Oxigen appealed to the Commission, which (after an inspector’s report recommending refusal) refused permission for the three reasons already outlined.

2.2 The Applicant’s Core Grounds

The grounds, distilled by Humphreys J, fell into three substantive clusters:

  1. Noise and air quality (Reason 2) – Oxigen argued the Commission “had no basis in law or fact” to find that the facility “would have the potential to seriously injure” nearby residential amenities by reason of air quality and noise, contending that:
    • its EIAR demonstrated compliance with EPA guidance and negligible impacts;
    • no contrary expert evidence was produced by the Commission or third parties; and
    • reliance on “potential” impacts was irrational and contrary to the legal test.
  2. Hydrology and groundwater (Reason 3) – Oxigen similarly asserted there was “no basis or evidence” for the conclusion that the proposed development had the potential to adversely affect the hydrological regime, water supply, or public health, arguing that:
    • its specialist hydrogeological assessments showed no material impact on recharge or groundwater; and
    • the Commission’s contrary finding was based on a “fundamental error of fact”.
  3. Development Plan / zoning (Reason 1) – Oxigen contended:
    • the lands were “white lands” in a rural area and not “zoned” in the sense relevant to para. 20 of the Fourth Schedule to the Planning and Development Act 2000;
    • the Commission erred in law by treating the lands as “zoned as Rural Policy Zone 2” and by characterising conflict with policy objectives EE55 and EE59 as a “material contravention”; and
    • in any event, a “material contravention” should be confined to development that fundamentally undermines a specific plan provision.

Oxigen also attempted to rely on a very late affidavit (Paul Chadwick, 3 October 2025) to buttress its technical criticisms; it further raised, but withdrew in oral submissions, a suggestion of bias (or conflict) based on the inspector’s prior employment with Louth County Council.

2.3 The Court’s Decision in Outline

Humphreys J dismissed the proceedings and refused all substantive and declaratory relief. In doing so, he held that:

  • the Commission’s conclusions on noise, odour, groundwater and development plan compliance lay squarely within its zone of evaluative planning judgment and were not irrational or unlawful;
  • the use of “potential” impacts is both lawful and required under the EIA Directive; the applicant’s argument to the contrary reflected a misreading of EU law;
  • the Commission was not obliged to accept or follow the EIAR’s conclusions merely because the EIAR was detailed and uncontradicted – it was entitled to assess and disagree with the developer’s expert evidence;
  • the onus of proof in environmental judicial review lies firmly on the applicant, which had failed to demonstrate any defect in the EIA, the reasoning, or the Commission’s expertise;
  • a material contravention can arise from conflict with general policy objectives in a development plan, not only from conflict with zoning objectives, and materiality is not confined to developments that “fundamentally undermine” a plan;
  • certain semantic imperfections in the decision (e.g. the use of “zoned” to describe a rural policy zone; “based on” the EIAR instead of “having regard to”) did not render the decision unlawful, because it could be read in a valid, sensible way; and
  • the late Chadwick affidavit was inadmissible – applicants must marshal their evidence at leave stage, and the expedited planning judicial review regime does not permit an open‑ended right to submit fresh “non‑reply” evidence shortly before trial.

The application was therefore dismissed, with a provisional indication of no order as to costs (subject to written submissions), and the Court gave detailed guidance on post‑judgment procedures and the handling of draft judgments.

3. Analysis

3.1 Precedents and Legal Framework

3.1.1 Evaluative Judgments and the Standard of Review

A central theme of the judgment is the limited role of the Court in reviewing evaluative planning judgments.

At para. 41(i), Humphreys J endorses the long‑standing position that:

  • the weight to be given to evidence is “quintessentially” for the decision‑maker (citing Birmingham J in M.E. v Refugee Appeals Tribunal [2008] IEHC 192, para. 27); and
  • where a decision involves a significant degree of planning judgment and is not affected by procedural, legal or factual errors, it is generally reviewable on an irrationality / unreasonableness standard, not by way of rehearing on the merits (citing the Supreme Court in Sherwin v An Bord Pleanála [2024] IESC 13, and Barr J in Graymount House Action Group v An Bord Pleanála [2024] IEHC 327).

This frames the Court’s approach: Oxigen’s challenge was required to identify a legal or procedural flaw or a conclusion so unreasonable that no reasonable authority could reach it. A simple disagreement with the Commission’s planning evaluation – which is what the Court repeatedly found the case amounted to – is insufficient.

3.1.2 Reading Administrative Decisions Sensibly

The judgment reiterates the increasingly firm line of Irish courts against hyper‑technical reading of planning decisions.

At para. 41(ii), citing a series of authorities (M.R. (Bangladesh) v IPAT [2020] IEHC 41; Rostas v DPP [2021] IEHC 60; St Margaret’s Recycling v An Bord Pleanála [2024] IEHC 94; Mulloy v An Bord Pleanála [2024] IEHC 86; Save Roscam Peninsula CLG v An Bord Pleanála (No. 6) [2024] IEHC 335; and the Supreme Court in E.M. v Minister for Justice [2024] IESC 3), he emphasises that:

  • decisions must, where possible, be read in a way that makes sense rather than in a way that renders them invalid;
  • the court should not select the most erroneous or strained reading of a text to justify quashing; and
  • “unhelpful” or imperfect phrases can often be reconciled with a lawful understanding when the decision is considered as a whole.

This principle is concretely applied to:

  • the phrase “based on” the EIAR in Reason 2 – read instead as “having regard to” (paras. 57–62); and
  • the description of the land as “zoned as Rural Policy Zone 2” in Reason 1 – treated as a loose but harmless shorthand for its designation as a rural policy area, not as a statement of formal zoning in the para. 20 Fourth Schedule sense (paras. 79–80).

3.1.3 Onus of Proof in Environmental Assessment Challenges

Humphreys J situates the case within a substantial body of jurisprudence on the burden of proof in environmental judicial review, particularly challenges to Environmental Impact Assessment (EIA) and Appropriate Assessment (AA).

At para. 41(iii), he compiles, and effectively re‑endorses, a line of authority which establishes that:

  • the onus rests on the applicant to demonstrate, usually by expert evidence or by pointing to patent flaws on the face of the materials, that an EIA or AA is legally or scientifically defective; and
  • apart from cases of non‑consideration of a mandatory factor or patent error, an allegation of inadequate scientific assessment must be supported by admissible expert evidence showing that reasonable doubt should have arisen, or that the decision‑maker’s conclusion was not open to a reasonable expert.

He draws on:

  • R v Crischuk 2010 BCSC 716 (and 2010 BCCA 391);
  • Reid v An Bord Pleanála (No. 1) [2021] IEHC 230;
  • the Supreme Court in An Taisce v An Bord Pleanála [2022] IESC 8 (Hogan J, para. 124);
  • Carrownagowan Concern Group v An Bord Pleanála [2024] IEHC 300 (leave to appeal refused: [2025] IESCDET 9);
  • Salmon Watch Ireland & Ors v Aquaculture Licences Appeals Board & Ors [2024] IEHC 421;
  • Minoa Ltd v An Bord Pleanála [2024] IEHC 704;
  • Nagle View Turbine Aware Group v An Bord Pleanála [2024] IEHC 603 (leave to appeal refused: [2025] IESCDET 41);
  • Kennedy v An Bord Pleanála [2024] IEHC 570;
  • Roache v An Bord Pleanála [2024] IEHC 311;
  • Ryanair DAC v An Bord Pleanála [2025] IEHC 74;
  • Donegal County Council v Planree [2024] IECA 300; and
  • the Supreme Court in O’Doherty and Waters v Minister for Health [2022] IESC 32.

This body of law defeats Oxigen’s implicit suggestion that because its EIAR was uncontradicted, the Commission was bound to accept it. The Court emphasises that the developer’s own technical material is not self‑validating.

3.1.4 Material Contravention and Development Plan Objectives

The judgment also engages with the concept of material contravention of a development plan.

At para. 41(iv), the Court relies on Sherwin v An Bord Pleanála [2024] IESC 13 and Maye v Sligo Borough Council [2007] IEHC 146 to reiterate that:

  • some plan provisions are highly specific and leave little room for evaluation;
  • others are general, even aspirational, and require a “greater degree of judgment” as to whether a development contravenes them and whether such contravention is material.

Section 37(2)(b) of the Planning and Development Act 2000 is quoted to confirm that material contravention is not confined to zoning objectives but relates to the development plan as a whole (para. 81–82).

Humphreys J then addresses the meaning of “material” (paras. 84–85), emphasising:

  • “material” is the opposite of “immaterial” or de minimis; it extends to any breach with a real, non‑trivial impact;
  • there is no third category between “material” and “immaterial”; and
  • the applicant’s suggestion that a contravention is material only if it “fundamentally undermines” a specific plan provision is inconsistent with the statutory scheme and ordinary language.

He distinguishes Freeney v An Bord Pleanála [2024] IEHC 427, explaining that the decision there effectively held that s. 37(2)(b) was not engaged on the facts, rather than laying down a restrictive definition of materiality (para. 85), and he references Leech v An Bord Pleanála [2024] IEHC 599 as an example where a failure even to acknowledge a contravention was important.

3.1.5 Case Management, Draft Judgments and Late Evidence

On procedure, the judgment is also noteworthy.

First, the Court gives detailed guidance on the use of draft judgments (paras. 34–35), drawing on:

  • O’Donnell C.J. in O’Sullivan v HSE [2023] IESC 11; and
  • O’Donnell J in O’Sullivan v Sea Fisheries Protection Authority [2017] IESC 75, [2017] 3 I.R. 751.

The key points are:

  • a draft judgment is a confidential, non‑public concession to parties, not a new phase of proceedings;
  • comments are strictly limited to errors, omissions, or issues such as redactions, not re‑arguing the case; and
  • parties must respond promptly and with focus; the Court may finalise judgment without listing further.

Secondly, and more directly relevant to planning litigation, the Court adopts a strict stance on late affidavits and the limits of reply evidence. Relying on:

  • Sliabh Luachra v An Bord Pleanála [2019] IEHC 888; and
  • Fahybeg Windfarm Opposition Group v An Bord Pleanála [2025] IEHC 310,

the Court held that the Chadwick affidavit (filed over 2½ years after proceedings commenced and 20 days before trial) was inadmissible (paras. 49–53). It stresses:

  • in expedited planning / environmental judicial review, an applicant must have its case and evidence substantially in place at leave stage;
  • further affidavits are limited to genuine reply, i.e. responding to new matters raised by the respondent; and
  • it is unfair and disruptive to “rewind the clock” by introducing substantial new evidence at the eleventh hour, particularly where it could have been filed at the outset.

This reinforces that developers (and objectors) must treat the leave stage as the point at which their evidential and legal case must be essentially complete.

3.2 The Court’s Legal Reasoning on the Substantive Grounds

3.2.1 Core Ground 1 – Noise and Air Quality (Reason 2)

(a) The Commission’s Reason 2

Reason 2 of the Commission’s refusal (para. 39) stated that:

“based on the information provided in the Environmental Impact Assessment Report, the nature, scale, siting, and operation of the proposed waste recovery and recycling facility would have the potential to seriously injure the residential amenities of properties in immediate proximity … by reason of air quality and noise effects.”

Key contextual facts included:

  • the waste facility generates odour of the type the EPA describes as the “most offensive” (para. 43);
  • it would operate effectively 24 hours a day in a rural setting close to houses;
  • HGV movements would occur from 07.00 to midnight six days a week; and
  • the site was unserviced and previously undeveloped greenfield land.

The inspector’s report elaborated on:

  • the visual impact and industrial character of a very large building near rural dwellings (paras. 44–47);
  • the close proximity of dwellings and the potential for odour and noise nuisance; and
  • concerns about siting such a facility in an unserviced rural area.
(b) Oxigen’s Arguments

Oxigen’s complaint (paras. 55–56) was that the Commission:

  • ignored its detailed EIAR, which:
    • modelled odour impacts within the 1.5 OUE/m³ guideline (the facility predicted 1.32 OUE/m³); and
    • concluded that operational noise would remain within EPA limits, with traffic noise impacts “negligible”;
  • had no contrary technical evidence from its own consultants or third‑party experts;
  • misapplied the EIA Directive by focusing on the potential to injure amenities, rather than actual or likely injury; and
  • had no evidential basis in law or fact for finding serious injury to residential amenity.

In its statement of case, Oxigen even pleaded that the proposal would cause “no odour” at receptor locations – a claim the Court found inconsistent with its own EIAR, which expressly modelled odour impacts (para. 56, citing the Commission’s submissions).

(c) The Court’s Response: Planning Judgment and EIAR Non‑Finality

The Court’s core answer is grounded in the notion of planning judgment.

First, the Court accepts that the EIAR concluded that odour and noise impacts would be within guideline values (paras. 59–61). However, it rejects the premise that this binds the Commission:

  • the Commission’s role is to assess the EIAR, not to “blindly accept” its conclusions (para. 56, quoting the Commission);
  • the Commission may legitimately take the EIAR’s modelling at face value (i.e. accept the predicted odour and noise levels) but disagree that such impacts are acceptable in planning terms, having regard to local context (para. 62); and
  • such a disagreement is an evaluative judgment on amenity and land-use suitability, not a scientific error.

Secondly, the Court emphasises that the Commission was entitled to have regard to the “most offensive” nature of the odour (per EPA guidance) and its frequency and duration at nearby dwellings. The inspector had referenced the FIDOL factors (Frequency, Intensity, Duration, Offensiveness, Location) from EPA guidance and concluded that, even if guideline concentrations were respected, the pattern of odour events at such close quarters was unacceptable in a rural residential setting (para. 56, Commission’s submissions, esp. §14–§15).

On noise, the Court again notes that, although guideline levels might be met, the facility would create an increase in noise levels at specific dwellings, particularly from HGVs. The acceptability of that increase is a matter of planning judgment (para. 56, §16–§18).

Thirdly, the Court firmly rejects Oxigen’s attempt to challenge the Commission’s technical expertise. It holds that:

  • the EIA Directive requires that appropriate expertise be available to the competent authority, not that every individual decision‑taker personally be an expert (para. 64); and
  • Oxigen had produced no evidence to show that expertise was lacking, nor had it sought discovery, interrogatories, or other steps to establish such a claim (para. 64).

Overall, the Court concludes that:

  • the Commission’s finding that air quality and noise impacts had the potential to seriously injure residential amenities was within its zone of evaluative judgment (para. 70(i)–(iii)); and
  • Oxigen had not demonstrated any legal error, irrationality or absence of evidential basis.
(d) “Potential” Impacts and the EIA Directive

A particularly important aspect of the judgment is the treatment of the word “potential”.

Oxigen argued that reliance on “potential” serious injury or “potential” impact was improper; in its view, a refusal reason should be based on actual or likely effects, having regard to mitigations and regulatory controls (para. 38(4), 56, 68).

The Court robustly rejects this, grounding its reasoning in the EIA Directive:

  • Article 7(4) of the EIA Directive refers explicitly to the “potential transboundary effects” of a project (para. 65);
  • Annex III (cited at para. 66) is titled “Type and characteristics of the potential impact” and requires consideration of, inter alia:
    • the probability of the impact;
    • the magnitude, intensity and complexity of the impact; and
    • the possibility of effectively reducing the impact.

From this, the Court concludes:

  • the Directive plainly requires the assessment of potential (possible) impacts, not only already-certain or fully quantified impacts (paras. 65–67);
  • the assessment must look at unmitigated impacts as well as mitigated impacts, since the possibility of mitigation and its effectiveness are themselves matters for evaluation (para. 67, 69); and
  • it is therefore a misreading of the Directive to regard the term “potential” as indicating a lower or improper standard.

The Court expressly agrees with the Commission’s submission that using the lexicon of “potential impact” – the very language of Annex III – cannot itself be a ground for certiorari (para. 68).

This is a key point of wider significance: the Irish courts are aligning explicitly with the risk‑based, preventive logic of EU environmental law, which is concerned with the potential for significant adverse effects and the adequacy of mitigation, not merely with proven or certain harm.

(e) Summary on Reason 2

In summary, the Court finds that:

  • Reason 2 was a lawful expression of the Commission’s evaluative planning judgment;
  • reference to “potential to seriously injure” residential amenities is consistent with, and indeed mandated by, the EIA framework;
  • the Commission was entitled to disagree with the EIAR’s planning conclusions (acceptability of impacts) even if it accepted the modelling outputs;
  • claims of inadequate expertise and absence of evidence were unsupported; and
  • the semantic complaint about “based on” the EIAR was cured by reading the decision sensibly as “having regard to” the EIAR.

3.2.2 Core Ground 2 – Hydrology, Groundwater and Public Health (Reason 3)

(a) The Commission’s Reason 3

Reason 3 (para. 39) stated that:

“Having regard to the information provided in the Environmental Impact Assessment Report in relation to geology, hydrogeology, and hydrology in the vicinity of the site, the Board is not satisfied that the groundwater reserves would not be significantly diminished by reason of abstraction and failure to recharge satisfactorily … The proposed development would have the potential to have a negative impact on water bodies … and would, therefore, be prejudicial to public health and contrary to the proper planning and sustainable development of the area.”

The key elements were:

  • concern that a combination of:
    • groundwater abstraction (up to c. 13.8 m³/day as backup to rainwater harvesting); and
    • reduction in natural recharge due to extensive building and hard surfacing,
  • could significantly diminish local groundwater reserves;
  • with knock-on impacts on nearby private wells and water bodies’ ability to achieve or maintain “Good” status under the Water Framework Directive; and
  • resultant risk to public health.

The inspector had highlighted:

  • the presence of three private wells within 100m of the site;
  • the absence of a detailed groundwater risk assessment, recharge analysis or defined zone of contribution (ZoC) in the EIAR; and
  • concerns raised by the Council’s Environment Section about missing data on wells and groundwater risk (para. 72–72, Commission’s summary at §26–§27).
(b) Oxigen’s Arguments

Oxigen argued (paras. 71–72) that:

  • its EIAR, prepared by specialist hydrogeologists, concluded that:
    • the required abstraction (13.8 m³/day) would not impact groundwater levels or flows; and
    • there would be no material effect on groundwater, private wells, or public health;
  • the Commission either misconstrued or ignored that expert evidence; and
  • the conclusion that groundwater recharge or reserves would be significantly affected was based on a “fundamental error of fact”.

In essence, Oxigen said that in the absence of contrary evidence the Commission was obliged to accept its hydrogeological assessment.

(c) The Court’s Response: Adequacy of EIAR and Deference on Evaluation

The Court again approaches the issue through the lens of evaluative judgment and onus of proof.

First, it notes that:

  • the EIAR did acknowledge the necessity for groundwater abstraction as backup (para. 73);
  • Table 9.9 of the EIAR itself recognised that abstraction “includes potentially lowering the water table reducing the resources for private groundwater users” (para. 72, §23); and
  • yet, subsequent tables in Chapters 9 and 10 appeared to simply assert that the impact would be negligible or non‑existent, without a detailed, transparent analysis of how that conclusion was reached, or of private wells’ susceptibility to drought (para. 72, §23–§25).

Secondly, the Court accepts as accurate the inspector’s and Council’s observation that there was:

  • no discrete, structured groundwater risk assessment focusing on:
    • recharge values;
    • the zone of contribution (ZoC) of the aquifer;
    • the capacity of private wells and their vulnerability in drought scenarios; and
  • an absence of “detailed investigations and analysis” of the impact on groundwater reserves (para. 72, §27).

Crucially, the Court notes that Oxigen had not directly pleaded or sworn any detailed challenge to the inspector’s factual assertions that such risk assessment and detailed analysis were missing (para. 72, §27–§28).

Thirdly, the Court reiterates (paras. 73–76) that:

  • it is for the Commission, not the developer, to judge whether the EIAR’s treatment of groundwater is adequate and whether residual risk is acceptable;
  • the applicant bears the burden of showing that the Commission’s dissatisfaction was unreasonable or unlawful; and
  • on the face of the material, there remained unresolved concerns about groundwater quantity (and its link to water quality and WFD objectives), so the Commission’s refusal was within its evaluative remit.

The Court expressly rejects any attempt to rigidly separate water quantity from water quality in the context of the Water Framework Directive, stating that the concept that they are “totally and completely separate is untenable” (para. 75).

(d) Summary on Reason 3

The Court’s conclusions can be summarised as follows (para. 76):

  • the Commission’s conclusion that the development had the potential to unacceptably impact groundwater, water supply and public health fell within its zone of evaluative judgment;
  • it is “manifestly incorrect” to say there was no evidential material on which the Commission could rely – the EIAR itself acknowledged potential impacts, and the absence of a discrete risk assessment was a legitimate concern;
  • Oxigen’s submission that the Commission was bound to accept its experts’ assurances misconceives the role of the competent authority under the EIA Directive; and
  • no legal error or irrationality had been established.

3.2.3 Core Ground 3 – Development Plan, Zoning and Material Contravention (Reason 1)

(a) The Planning Policy Context

The site lay in a rural area designated as Rural Policy Zone 2 (Area Under Strong Urban Influence) in the Louth County Development Plan 2021–2027.

Section 5.19.3 (“Rural Enterprises”) of the Plan (para. 42) emphasises:

  • the importance of rural enterprises to local employment; but
  • the need to strike a balance between supporting rural enterprises and protecting the local environment; and
  • that “in the first instance, new employment related developments are directed to settlements where services are available and lands have been identified for employment uses”.

It also notes that some developments may be more appropriate in rural areas due to locational or resource‑specific factors or national/regional importance, and refers to the creation of an Economic Business Zone at Carrickcarnan as a strategic employment area.

Two policy objectives were central:

  • EE55: “To support rural entrepreneurship and rural enterprise development of an appropriate scale at suitable locations in the County.”
  • EE59: “To secure vibrant and viable rural communities by supporting the development of rural based enterprises.”

The inspector concluded that:

  • the proposal was an “industrial type” development of substantial scale, visually and functionally out of character with its rural setting and close dwellings (paras. 44–47);
  • it was not of “an appropriate scale” nor at a “suitable location” within the meaning of EE55; and
  • it would not secure vibrant and viable rural communities as contemplated by EE59 (para. 47).

She therefore regarded the proposal as a material contravention of the development plan.

(b) The Commission’s Reason 1 and Oxigen’s Challenge

Reason 1 (para. 39) stated that:

  • the site is “located in a rural area on lands zoned as Rural Policy Zone 2 (Area Under Strong Urban Influence)”;
  • the policies and objectives of the plan (in particular EE55 and EE59) direct employment activities to settlements or appropriate rural locations;
  • considering the existing nearby residences, the principle of locating a waste processing facility on this unserviced site would be unacceptable and outside the scope of the economic and rural objectives of the plan; and
  • accordingly, the development would materially contravene the development plan objectives and be contrary to proper planning and sustainable development.

Oxigen’s challenge (paras. 77–78) focused on:

  • the use of the word “zoned” – contending the lands were “white lands” and that the Commission had incorrectly treated EE55 and EE59 as zoning objectives for the purposes of para. 20 of the Fourth Schedule (which deals with refusals based on material contravention of zoning objectives and is relevant to compensation claims);
  • arguing that the Commission misunderstood the nature of EE55 and EE59 and that these objectives “do not justify” the refusal basis adopted; and
  • submitting that, even if there was a contravention, it was not “material” unless it fundamentally undermined a plan provision.
(c) Semantics of “Zoning” and the Valid-Reading Principle

Humphreys J accepts that the word “zoned” in Reason 1 is “not the best” choice (para. 79). However, he holds that:

  • in context, it is clear the Commission was referring to the designation of the area as a Rural Policy Zone 2 area within the plan, not to a conventional land‑use zoning (such as “industrial”, “residential”, etc.);
  • the decision can and should be read as meaning that the lands are described as lying within Rural Policy Zone 2, subject to EE55 and EE59; and
  • under the established principle that decisions should be read in a way that makes sense if that is available (para. 41(ii), 79–80), this semantic imperfection does not invalidate the decision.

This reasoning also underpins the Court’s refusal to grant a declaration on para. 20 of the Fourth Schedule. Both parties accepted that:

  • the refusal did not purport to be based on a contravention of a zoning objective as defined in para. 20; and
  • EE55 and EE59 were not treated by the Commission as zoning objectives (para. 88–89).

Recording that para. 20 was not engaged in this case was sufficient; there was no live controversy warranting declaratory relief.

(d) Material Contravention of Non‑Zoning Objectives

The more substantive point is the Commission’s ability to treat conflict with non‑zoning policy objectives (EE55 and EE59) as a material contravention.

The Court holds (paras. 80–83) that:

  • policy objectives such as EE55 and EE59 are general and evaluative in nature – determining whether a particular proposal is of an appropriate scale at a suitable location, and whether it supports vibrant rural communities, inherently involves planning judgment;
  • Section 37(2)(b) of the 2000 Act refers to contravention of the development plan generally, and is not limited to zoning objectives;
  • accordingly, the Commission was entitled in principle to find a material contravention by reason of conflict with these policy objectives, even though they are not land‑use “zoning” objectives; and
  • no misinterpretation of the development plan had been shown.
(e) The Threshold of “Materiality”

Oxigen argued that even if EE55/EE59 were contravened, the contravention was not “material” unless it “fundamentally undermined” a specific provision of the plan.

Humphreys J firmly rejects this linear, high threshold (para. 84):

  • “material” is properly understood as anything above the zone of immateriality or de minimis impact – any breach that could really affect the implementation of the plan or the planning balance is material;
  • contraventions that make “absolutely no difference” (truly immaterial) are non‑material; but once a breach has a real-world planning impact, it passes the threshold;
  • there is no third category between “material” and “immaterial”; and
  • to require “fundamental undermining” would be inconsistent both with ordinary language and the legislative intent.

In practical terms, placing a large, industrial‑type MBT facility on an unserviced rural site in a policy zone that channels significant employment uses to serviced settlements and emphasises environmental protection was clearly capable of being regarded as a material departure from EE55/EE59 and the overall rural strategy.

(f) Overall Conclusion on Reason 1

The Court concludes (paras. 83, 90):

  • it was for the Commission, exercising planning judgment, to decide whether the proposal complied with EE55 and EE59;
  • the finding that the development fell outside those objectives and constituted a material contravention was within its evaluative remit;
  • the semantic use of “zoned” did not amount to an error of law; and
  • no basis had been established for certiorari or for the declaration sought regarding zoning status or para. 20 of the Fourth Schedule.

3.3 Treatment of Evidence, Pleadings and Procedure

3.3.1 Late Evidence and the Chadwick Affidavit

One of the more practically important aspects of the judgment is its stance on late evidence.

Oxigen sought to rely on a detailed affidavit of Paul Chadwick sworn on 3 October 2025, barely 20 days before the substantive hearing on 23 October 2025, in proceedings commenced on 22 March 2023. The affidavit contained extensive technical criticism of the inspector’s and Commission’s reasoning, much of which corresponded to points that could have been made at the outset.

The Court excluded the affidavit as inadmissible (paras. 49–53), for several reasons:

  • under O.103 RSC, Practice Direction HC126 and planning list directions, reply affidavits are limited to genuine replies to new matters raised by respondents; they are not an occasion to expand or reconstruct the applicant’s core case;
  • the Chadwick affidavit went “far beyond” anything properly called reply (para. 52);
  • no satisfactory explanation was given for the excessive delay, mirroring the approach in Sliabh Luachra v An Bord Pleanála [2019] IEHC 888 (quoted at para. 51);
  • allowing it would be unfair to the Commission, which would have insufficient time to respond and could face “procedural chaos” (para. 50); and
  • the expedited nature of planning and environmental judicial review requires applicants – particularly experienced corporate applicants – to conduct litigation with appropriate discipline and to have their evidential case ready at leave stage (paras. 49–52).

The Court also notes a conceptual problem: if Chadwick was simply restating points already made in the pleadings and existing evidence, his affidavit was superfluous; if he was adding new material, it was unpleaded and inadmissible (para. 51(C)).

3.3.2 Pleadings and “New” Arguments

Closely related is the Court’s insistence on fidelity to the pleadings. Humphreys J accepts the Commission’s submission that various arguments raised in submissions – such as:

  • new “reasons” challenges;
  • claims about failure to weigh conflicting policies; and
  • attacks on the Commission’s expertise –

were not pleaded in the statement of grounds and thus could not be advanced (para. 48).

This underlines that applicants must frame their legal challenges precisely at the outset. Attempting to expand or re‑shape the case in legal submissions, unmoored from pleaded grounds, will not be entertained.

3.3.3 Bias / Conflict of Interest Allegation

Although Oxigen wisely withdrew its suggestion of bias arising from the inspector’s previous employment with the Council, the Court makes a brief but important comment (para. 9):

  • the mere fact that an inspector previously worked for the local authority involved in a case does not in itself create an appearance of bias for a reasonable, well‑informed person;
  • people are expected to leave prior institutional affiliations at the door when taking on a new role; and
  • the passage of time makes this separation easier.

This is a useful clarification for the planning system, which often employs professionals who move between local authorities, boards and consultancies.

3.4 Impact and Significance

3.4.1 For Planning Authorities and An Coimisiún Pleanála

The judgment strengthens and clarifies several aspects of planning decision‑making:

  • Confidence in evaluative judgment: The Court affirms that the Commission may:
    • decline to accept a developer’s EIAR “conclusions” on acceptability even where technical modelling appears to show compliance with guidance; and
    • determine, for example, that the frequency and offensive nature of odour in close proximity to dwellings is unacceptable, even if guideline concentrations are not exceeded.
  • Use of “potential” impacts: Planners may lawfully frame their reasoning in terms of the potential for serious impacts, consistent with the EIA Directive’s requirement to assess potential and probable effects and the effectiveness of mitigation.
  • Material contravention of non‑zoning objectives: Development plans may be robustly applied via “material contravention” findings where proposals conflict with general rural enterprise or environmental objectives, not only with zoning maps.
  • Reading decisions as a whole: While decisions should still be carefully drafted, courts will not readily quash based on sub‑optimal phrasing that can reasonably be read in a lawful way.

3.4.2 For Developers

For developers, particularly in the waste and heavy infrastructure sectors, the judgment carries several cautionary lessons:

  • EIAR is not conclusive: A well‑prepared EIAR, even if uncontradicted, does not guarantee acceptance of its conclusions. Decision‑makers retain a wide margin to interpret whether residual impacts are acceptable in context.
  • Guideline compliance vs planning acceptability: Demonstrating compliance with regulatory or guideline thresholds (e.g., odour concentrations, noise levels) does not preclude a refusal based on residential amenity or rural character, especially where impacts are of an inherently offensive type and proximate to homes.
  • Rural sites and “industrial” uses: Locating large, industrial‑type facilities on unserviced rural land close to dwellings is inherently high‑risk in planning terms, particularly where the development plan clearly channels employment uses to serviced settlements.
  • Front‑loading of evidence: Developers must expect to marshall all necessary expert evidence – including rebuttal evidence where appropriate – at or before the leave stage in judicial review. There is no entitlement to “top up” the record shortly before hearing with new technical material.
  • Limited scope for merits‑based challenges: Courts will not re‑weigh planning judgments. A judicial review that amounts to “this case screams merits disagreement” (as paraphrased at para. 1) is unlikely to succeed.

3.4.3 For Community Objectors and Environmental NGOs

The judgment also has implications for community groups and NGOs:

  • Support for cautious approach: It confirms that decision‑makers may legitimately refuse where they identify potential adverse environmental or amenity impacts – grounding that approach firmly in EU law.
  • Burden of proof equally applies: However, where objectors bring judicial review, the same onus principles apply: they must support claims of EIA/AA defects by appropriate evidence; mere assertion is not enough.
  • Procedural discipline: The strict approach to pleadings and late evidence applies equally to objectors. They too must treat leave as the point at which their evidential case is largely complete.

3.4.4 Systemic and Doctrinal Significance

Finally, in doctrinal terms, the case:

  • reinforces the Irish courts’ alignment with EU environmental principles by:
    • endorsing risk‑based consideration of “potential” impacts; and
    • emphasising that unmitigated impacts must be understood in order to assess mitigation adequacy;
  • clarifies and modestly develops the law on material contravention, especially with respect to:
    • non‑zoning objectives; and
    • rejection of an artificially narrow “fundamental undermining” test of materiality;
  • contributes to the ongoing jurisprudential consolidation of:
    • the limited function of judicial review vs merits appeals; and
    • the obligation to read administrative decisions in a fair, holistic manner.

4. Complex Concepts Simplified

4.1 Evaluative Judgment

An “evaluative judgment” is a decision that involves weighing multiple factors, often including:

  • technical information (e.g. noise levels, odour modelling);
  • policy objectives (e.g. supporting rural enterprise vs protecting amenity); and
  • local context (e.g. proximity to houses, rural character).

Courts generally do not substitute their own view for this balancing exercise unless:

  • the decision maker ignored a legally mandatory factor; or
  • the conclusion is so unreasonable that no reasonable decision maker could reach it.

4.2 EIAR and EIA

An Environmental Impact Assessment Report (EIAR) is a document prepared by or for the developer, describing:

  • the proposed project;
  • the baseline environment (air, water, noise, biodiversity, etc.);
  • the likely significant environmental impacts; and
  • mitigation measures and monitoring proposals.

The Environmental Impact Assessment (EIA) is the process carried out by the competent authority (here, the Commission) of:

  • examining the EIAR and other information; and
  • reaching a reasoned conclusion on the likely significant effects.

The EIAR is input, not the final word. The authority can disagree with it.

4.3 “Potential” Impacts and Unmitigated Effects

Under the EIA Directive, authorities must look at potential impacts, including:

  • how likely they are (probability);
  • how bad they could be (magnitude, intensity); and
  • whether mitigation can effectively reduce them.

To judge whether mitigation is sufficient, they need to understand what would happen without mitigation – the “unmitigated impact”. From there, they can assess:

  • whether mitigation is reliable; and
  • whether residual impacts are acceptable.

That is why “potential” and “unmitigated” impacts are both central concepts, not legal flaws.

4.4 Material Contravention

A material contravention of a development plan occurs when a proposed development significantly departs from any of the plan’s objectives – such as:

  • zoning objectives (e.g. “industrial”, “residential”); or
  • policy objectives (e.g. directing new employment to serviced settlements; protecting rural amenity).

A contravention is:

  • immaterial if it makes no real difference in planning terms (e.g., a trivial numerical discrepancy);
  • material if it has a real planning impact, even if it does not completely frustrate the plan.

The Court confirms that there is no additional category requiring “fundamental” undermining of the plan.

4.5 Groundwater Risk Assessment and Zone of Contribution (ZoC)

A groundwater risk assessment typically examines:

  • the geology and hydrogeology (rock types, aquifer characteristics);
  • how water recharges the aquifer;
  • the zone of contribution (ZoC) – the area of land from which rainfall feeds a particular well or spring; and
  • the potential effects of abstraction or development on groundwater levels and supplies.

For rural homes dependent on private wells, changes in recharge or abstraction within the ZoC can affect:

  • whether wells run dry in dry periods; and
  • water quality (e.g. concentration of pollutants).

In this case, the concern was that a large building and rainwater harvesting system on a site with high natural recharge, combined with abstraction, could reduce groundwater resources supporting nearby wells, without adequate risk analysis to rule this out.

5. Conclusion

Oxigen Environmental Unlimited Company v An Coimisiún Pleanála [2025] IEHC 632 is an important addition to Irish planning and environmental jurisprudence, particularly in the context of waste infrastructure and rural development.

The judgment reinforces several core principles:

  • Planning as evaluative judgment – Courts will not second‑guess An Coimisiún Pleanála’s rational, lawfully‑reached assessments of residential amenity, environmental risk, and development plan compatibility, even where those assessments differ from a developer’s expert evidence.
  • Centrality of “potential” impacts – The EIA Directive compels authorities to focus on potential and unmitigated impacts, and to weigh the effectiveness of mitigation. The use of “potential to seriously injure” is not a weakness but a reflection of proper legal analysis.
  • Non‑binding nature of EIAR conclusions – A developer’s EIAR is an essential input but not the final word. The competent authority is entitled – and indeed obliged – to critically interrogate and, where appropriate, depart from the developer’s conclusions.
  • Material contravention of policy objectives – Material contravention is not confined to zoning maps. Conflict with general rural enterprise and environmental objectives in a development plan can justify refusal, subject to the usual evaluative judgment.
  • Procedural discipline in planning judicial review – Applicants must come to court with their case fully prepared from the outset. Late evidence and unpleaded arguments will not be tolerated in the expedited planning list.

Substantively, the case confirms that a large, 24‑hour waste facility generating highly offensive odour and increased noise, located on an unserviced rural site in close proximity to dwellings, may be refused notwithstanding detailed modelling showing guideline compliance, where the decision‑maker considers that the nature, location, and residual risk render it unacceptable.

Doctrinally, the judgment solidifies the trajectory of Irish planning law towards:

  • respect for the autonomy and expertise of planning authorities and the Commission in evaluative matters;
  • faithful integration of EU environmental principles, particularly risk‑based assessment of potential impacts; and
  • pragmatic, non‑technical reading of administrative decisions, avoiding quashing on the basis of mere drafting imperfections.

For practitioners, the message is clear: where a judicial review is essentially a merits disagreement with a planning judgment on amenity, risk or development plan policy, and no clear legal or procedural flaw is demonstrated, the courts will not intervene.

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