Consultation outcome

Response document: Environmental Assessment Levels for the amine-based carbon capture process

Updated 17 June 2025

1. Introduction

Regulation is the lifeblood of the Environment Agency. We face a rapidly changing world; our role as an environmental regulator is crucial to supporting the country’s transition to meet significant challenges whilst still maintaining high levels of protection for the environment and communities. Our regulatory approach can help ensure compliance, foster investment and drive innovation in areas like climate change adaptation, net zero and the circular economy.

Post-combustion carbon capture technologies using amine-based solvent systems to absorb carbon dioxide are an emerging approach to reducing carbon emissions from fossil fuel energy production. Carbon capture installations are permitted by the Environment Agency under the Environmental Permitting Regulations (England and Wales) 2016, as amended.

The carbon capture process may release small quantities of spent amine-based solvents and their transformation products to air under normal operating conditions. The Environment Agency uses Environmental Assessment Levels (EALs) to identify and mitigate potential operational risks of these chemicals through the permitting process. EALs are defined as ambient concentration of a pollutant in air with no appreciable risk or minimal risk to human health. In applying for a permit, operators are required to assess that emissions from their proposed facilities do not exceed the relevant EALs.

To support industry in permit application, the Environment Agency developed EALs for a number of amines and amine derivative products associated with the carbon capture process. The derivation applied our updated approach to developing EALs, based on available toxicological data and information for individual compounds. We agreed the approach with the UK Health and Security Agency (UKHSA). In our consultation, we presented the derived EALs, as well as a proposed approach to establishing EALs in situations where insufficient toxicological data is available.

2. How we ran the consultation

We ran the consultation over a period of 12 weeks from 17 January to 13 March 2025.

We completed our consultation process online, advertising it both on GOV.UK and on our Citizen Space consultation website. Alongside this we contacted over 700 potentially interested parties by email to let them know that the consultation was live. We also presented to both the Carbon Capture and Storage Association (CCSA) and Institute of Air Quality Management (IAQM) to give them information about the consultation and the opportunity to ask questions.

We received 10 responses to our consultation, including responses by Citizen Space and email. Of those responses, 4 were from industry, 4 were from energy operators and 2 from members of the public.

3. Summary of key findings and actions we will take

The responses have provided us with an understanding of the impacts that the EALs proposed will have on industry and on the public.

3.1 Main themes

Concerns were raised about the derivation of the EAL for aminomethylpropan-1-ol (AMP).

Working with the UKHSA, we will review the additional evidence provided and consider revising our proposed value before we publish it. We will share our decision, including a timescale for publishing an EAL for AMP. This will not delay the publication of the EALs for other substances included in the consultation for which no specific concerns were raised.

Several respondents requested that EALs were developed by the Environment Agency for further amines and their degradation, and that on their own, the current set of EALs was insufficient.

We recognise the need for further EALs to support the carbon capture sector and will publish our plans to derive further guidelines soon. In the absence of Environment Agency-derived EALs, operators should continue to derive their own EALs using our published methodology.

In the absence of an EAL published by the Environment Agency, concerns were raised over the complexity of and resources needed for the read-across process for the derivation of EALs by applicants to support specific permit applications.

We have recently published updated guidance on the derivation of EALs that sets out a robust and scientific approach, led by the available evidence on the mammalian and human toxicity of substances. Read-across is a recognised method used by organisations to assess the hazard and the risk to public health in the absence of data on the chemical properties and toxicity of a particular substance in the support of regulatory decisions around chemical use. We will work with applicants to develop pragmatic ways to manage the risks associated with low level releases of breakdown products and protects public health.

Technology providers don’t always know what’s in the solvents so will find it hard to plan with so few EALs.

We would encourage providers to talk to us early about their plans as we are committed to ensuring innovators have the support they need from us for their activities. This is instrumental in transforming the UK into a leading global innovator for clean energy and the circular economy. We will complete additional work to derive more EAL values. It is important that technology providers understand what is in their solvents and will be emitted into the air and, if there is potential for a pollutant to be emitted, to let us know via a permit application. We can then look at a suitable EAL proposed based on a derived value, or the compounds for which EALs have been derived, and use this as a proxy or ‘worst case’ for other compounds if appropriate. Without this info we will be unable to determine the permit.

Respondents highlighted that EALs should be based on pooled data, such as that collected under EU REACH, and that most amines and their derivatives were likely covered by such repositories.

Our methodology considers a wide range of data sources including the summary information provided by industry under EU REACH, which are synthesised to provide a robust and scientific opinion on the available evidence. However, the summary information available under EU REACH is often not sufficient to enable us to draw robust conclusions and the detailed supporting reports are usually not available to us due to third-party non-disclosure agreements. We would encourage applicants and manufacturers to provide this information directly to us for consideration; however, by doing this it would make the data publicly available. While we can look at values derived by other countries it’s still important for us to derive our own values to ensure we are confident the values are protective.

It is suggested that if new solvents are developed which use a mixture of amines, there may not be an EAL readily available for these. Consequently, this may delay or exclude the introduction of future solvents which may be of lower environmental impact.

Again, in these situations, operators can use our methodology document to develop new EALs for themselves. We are always happy to work with industry to support innovations that protect and enhance the environment so would encourage providers to talk to us. EALs for proxy compounds may also be an option, based on the structure or category of amines in new mixtures.

We would also like to see the UK regulators maintain a public database of approved EALs relating to amines and their derivatives once these have been accepted as valid in air quality assessments accompanying permit applications. This should include where these have been developed and accepted from the ‘Methodologies for the derivation of EALs with minimal data available’ approaches.

We publish values for EALs derived by the Environment Agency on GOV.UK. EALs developed by individual operators and agreed for use in our permits will be available on the public register. We would not publish these EALs to provide a database, although an independent organisation may consider doing so, and we have discussed this with the CCSA. UKHSA does not approve operator-derived EALs but considers the proposed values, other evidence and the estimated process contributions to evaluate the potential for health risk. Therefore, just because a permit is approved with a specific operator-derived EAL value does not mean UKHSA might not have concerns in a different set of circumstances.

One respondent identified the need to apply the precautionary principle in the derivation of EALs for amines and their breakdown products.

Our method for the derivation of EALs is based on the scientific review of available evidence; and the level of uncertainty, which includes the completeness of the available database on toxicology information and applying uncertainty factors (UFs). The UF approach is consistent with that applied to the protection of health from exposure to chemicals across a range of circumstances including air, food and drinking water. Where there is insufficient information available, and read-across is not applicable, we will not propose an EAL for that substance.

It was highlighted that the EALs apply to single sites. However, because the rollout of carbon capture usage and storage is based on industrial clusters, there will actually be cumulative emissions across the cluster. Whatever EALs are derived, by whatever method, they must apply to the cluster not the individual site – otherwise, communities and habitats will be exposed to dangerous levels of amines and their derivatives.

This has been at the forefront of our thinking and we have recently carried out a 4-year review of the environmental capacity needed for the deployment of proposed carbon capture and storage and hydrogen in key English industrial clusters. We will continue to work with industry and local government to provide technical advice ensuring that environmental capacity considerations are embedded into their strategic planning as well as individual project design. Currently we take this into account when the permit application is made. Background concentrations and any other contributions from existing or planned sites are taken into consideration where relevant.

There will be a requirement for continuous measurement due to short term exposure limits. There isn’t continuous monitoring technology.

We are aware of this issue and will be looking to work with the research community and industry to develop solutions.

Regular reviews of monitoring requirements should be conducted as technology evolves to ensure the framework remains both practical and effective.

We agree and this is part of our permit review and also our work on UK BAT (Best Available Techniques).

Development of EALs for amine mixtures provides additional challenges. The development of further guidance for determining an EAL for amine mixtures would be beneficial.

We would expect substances in a mixture to be identified and considered individually with toxicity specific EALs. The Environment Agency is looking to develop further EALs which could be helpful for individual pollutants.

The consultation states that ‘read across’ is a formal and accepted toxicological assessment process, however no references or supporting information is provided. We would like to see the publication of clear guidance in relation to the methodology for read across, accompanied by reference papers and examples.

We have published a methodology for the scientific derivation of EALs. This includes references for locations of guidance for these methods.

We would support the publication of guidance on the level of evidence required to support the characterisation of amines or N-amines as less toxic than the worst-case representative. Would this require specific toxicology testing (such as Ames tests) or would general trends identified in literature reviews be sufficient? Also, it would be helpful if guidance can be provided on what non-human, non-animal toxicity studies would be acceptable to support EAL derivations (such as Ames tests) to support EAL derivation.

We are working with others including the UKHSA to understand the role that non-animal assessment and/or testing methods for the toxicity of substances could potentially play in the future in setting EALs both in terms of hazard identification and characterisation.

Respondents raised concerns that an absence of an EAL may result in delays in the implementation of new innovative and less harmful solvents.

We have recently published updated guidance on the derivation of EALs that sets out a robust and scientific approach that is led by the available evidence on the mammalian and human toxicity of substances. In the absence of a published EAL, applicants should factor the time and resources needed for EAL development into their planning and permitting process. The Environment Agency is happy to provide advice and guidance.

3.2 Costs

In answer to the question regarding additional costs to industry that may result from implementation of the new EAL values proposed, we received the following responses:

• Industry may need to engage third parties for peer review, suppliers for toxicology study resource and laboratories if further tests are required. In-house expertise in environmental assessment and toxicology are also required to derive the EAL.
• There will be risks to project deployment pre-FID (financial investment decision) and post-FID, including completing FEED (front-end engineering design) studies, impact assessments and construction.
• Delays to project deployment due to the time taken to derive a specific EAL, may lead to a significant increase in development expenditure (DEVEX) and capital expenditure (CAPEX) costs.
• Additional costs may be linked to over-engineering to meet an EAL that is not certain, like oversizing stack heights, applying unnecessary reheating or applying un-needed abatement such as acid-washes
• In case of significant changes to an EAL (for example, subsequent to publication of new toxicology studies), this might require additional abatement and mitigation methods or engineering and plant design changes such as changing stack heights, water wash, changes to the plant configuration which can significantly increase the overall costs of the project and create further delays.
• Changes or replacement of the solvent itself could affect energy dynamics and the project’s operational costs.
• Costs may be associated with energy penalty and additional water resources, including planning for wastewater treatment that might or might not be needed based on the derived EAL.
• Some carbon capture projects are using existing EALs of proxy chemicals or chemicals which are similarly structured as the base of preliminary environmental impact assessment. Thus, depending on new EAL levels imposed, there will be possibility of major changes to the carbon capture plant design and planning.
• Given the extremely low proposed EAL for AMP of 9 ng/m³, very severe impact on the CAPEX of a carbon capture and storage facility using AMP as part of the absorption solvent is certain. The emission control systems to be applied would have to perform substantially better than what can be expected from BAT technology today. In worst case, the cost increase and the remaining technical risk will be too significant to offer the process and product to the UK market, reducing project viability and inhibiting or completely preventing carbon capture projects from proceeding.
• At a carbon capture plant in Germany, testing has shown emission concentrations of amines at the point of discharge to be greater than the EALs for both AMP and piperazine. Whilst the EAL relates to impacts on human health, it demonstrates that further ‘real-world’ understanding is needed and included in further developments of national EALs and project-specific EALs.
• If a future EAL is developed and found to be higher than that based on the ‘Methodologies for the derivation of EALs with minimal data available’ section, then projects may have invested in unnecessary complex designs with the added expenditure, which could potentially affect investment decisions on future carbon capture projects.

We have taken the concerns raised about these additional costs into consideration. Once a site has been granted a permit, the site would be able to operate at the agreed EAL level. Should evidence show a lower EAL would be more appropriate, this would be considered at the time of regular sector permit review. Should the evidence show that the EALs we have consulted on be necessary for the protection of human health, and this was not achievable by operators, we would expect sites to consider alternative solvents for their process.

It should be emphasised that EAL values are not expected emission concentrations at the point of discharge. Rather, they represent the maximum concentrations to which humans should be exposed at ground level, to be used in risk assessment modelling.

With regards to costs of any delays whilst the Environment Agency checks EALs derived by operators, it is worth noting that the more evidence provided to explain the derivation of chosen EALs, the easier the process of the Environment Agency in checking the values.

We recognise the potential additional costs associated with EAL derivation and are looking for information from our consultees on the magnitude of these costs. In-house expertise may not be necessary but outsourcing to appropriate consultancies may be.

We are committed to providing effective and proportionate resource to ensure that innovators have the support they need from us for their activities; this is instrumental in transforming the UK into a leading global innovator for clean energy and the circular economy.

3.3 Additional points raised by the consultation responses

Not every affected or interested community group will have access to a graduate chemist. We believe that there is a public interest need for accessible summary information for such communities.

Technical summaries on EAL derivation for each of the individual compounds were included in the consultation document. They are shortened versions of the detailed EAL derivation process, designed to provide accessible information.

The consultation is framed, particularly Q7 to Q11, for the benefit of industrial interests not for the affected communities. This suggests an example of a public body only serving private interests, when it must have a duty to serve the public interest first.

The EALs have been derived for the protection of human health and are created specifically for public interest. The consultation is designed to present the information and to obtain feedback from both the industries that will need to apply these EAL values, and the public that may be exposed to them. We are committed to providing information in a way that is accessible to non-specialists and will share this feedback with colleagues across the Environment Agency for future technical consultations.

We would like to express concern that this proposed EAL value for AMP has not been communicated properly prior to the EAL Development consultation (there was incorrect information on the proposed EAL values on the consultation website – previously it was 0.007 mg/m³ for 24 hour mean then changed to 9 ng/m³ for 24 hour mean, both for long term EAL).

We apologise for the inconvenience this caused. The value was corrected as soon as the error was noted.

The development of project specific EALs by different project developers using the alternative methodologies where minimal data is available could result in great variability for EALs developed for the same amine. This potential variability in project specific EALs across different projects for the same amines could potentially result in the following negative outcomes to projects: the UK regulators may require operators to retrospectively apply newly derived EALs; and members of the public and key stakeholders could be concerned to see different EALs being applied to different projects.

All project specific EALs will be thoroughly checked by the Environment Agency and reviewed by UKHSA taking into consideration the public health risks associated with an air emissions risk assessment. We would not expect significant differences in EALs applied to different projects.

Breakdown products will unlikely be known to developers of carbon capture plant, and any information that can be obtained during the project development stages will have an associated level of uncertainty. Whilst developers and operators of carbon capture plant can optimise the plant design and operate the plant to manage degradation of the solvents, the actual breakdown products cannot be guaranteed.

In this case the most precautionary EAL should be used for breakdown products until better information is made available to the operator.

4. Next steps

We have used the responses from this consultation to review and determine whether the EALs consulted on are appropriate for publishing. The information we have received has led us to conclude that we should proceed with publication of 6 of the 7 EALs consulted on immediately; we are still assessing further evidence provided on aminomethylpropan-1-ol (AMP) so this is currently excluded from the updated EALs for further review. 

We will publish on GOV.UK the new EAL values for the substances for which the evidence has shown we can proceed and start to use the new EALs in our regulatory activities.

Responses will also help us to determine how much of an impact the derived EALs and the derivation of future EALs will have on relevant parties.