Consultation outcome

Consultation response document: new EALs for emissions to air

Updated 3 September 2021

1. Background

The Environment Agency uses environment assessment levels (EALs) to judge the acceptability of proposed emissions to air from industrial processes, and their relative contribution to the environment. EALs represent a pollutant concentration in ambient air at which no significant risks to human health are expected.

In December 2011, we ran a consultation to identify a new hierarchy for the derivation of EALs. We made a commitment that before introducing any new EALs, we would hold a further round of public consultation to ask for comments on proposed substance-specific levels. We would then consider the comments before adopting them.

There are currently 88 substances with EALs published to the GOV.UK guidance Air emissions risk assessment for your environmental permit. Working with Public Health England (PHE), in 2020 we derived new EALs for 9 existing substances and 2 new substances, using the revised methodology. We ran a formal consultation between November 2020 and February 2021 on the new EAL values. In the consultation we also proposed to withdraw the published EAL for one substance, arsenic, relying instead on the environmental standards set out in the Ambient Air Directive.

This document presents the results of the consultation and how we will implement the new EALs.

The consultation sought the views of operators of regulated facilities, members of the general public, trade bodies, non-government organisations and others who may be affected by implementing the new EALs. The review of the evidence for each substance and the derivation of each EAL was undertaken in close cooperation with PHE.

To support the public consultation we summarised information in a dossier on how we had arrived at each EAL. The proposed changes were presented in this summary table.

Proposed EALs based on new methodology

Pollutant Current short-term (1hr) EAL (µg/m3) Current long-term EAL (µg/m3) Proposed new short-term EAL (µg/m3) Proposed new long-term EAL (µg/m3)
Arsenic - 0.003 - 0.006 A
Benzene 195 5 30 D No change
Chloroform 2,970 99 100 B, C Withdraw LT EAL
Chromium VI - 0.00025 No change No change
Ethylene dichloride 700 42 Withdraw ST EAL 3
Methyl chloroform 222,000 11,100 5,000 B, C Withdraw LT EAL
Mono-ethanolamine No current EAL No current EAL 400 100 B
Naphthalene 8,000 530 3 B, C Withdraw LT EAL
N-nitrosodimethylamine (NDMA) No current EAL No current EAL None proposed 0.2 ng/m3
Tetrachloroethylene 8,000 3,450 40 B, C Withdraw LT EAL
Trichloroethylene 1,000 1,100 Withdraw ST EAL 2
Vinyl chloride 1,851 159 1300 D 10

Notes

Note A

4th Daughter Directive (2004/107/EC) target value is a level fixed with the aim of avoiding, preventing or reducing harmful effects on human health and/or the environment as a whole, to be attained where possible over a given period.

Note B

24 hour mean value.

Note C

The current short and long-term EALs have been replaced by one 24-hour mean value.

Note D

The current short-term EAL has been replaced by a 24-hour mean value.

2. How we ran the consultation

The EAL consultation document and supporting dossier were available for public consultation on Citizen Space from 2 November 2020 to 7 February 2021. The consultation was accompanied by a consultation response form and the questions are set out in Appendix B.

We promoted the consultation through:

  • emails to a wide range of trade bodies who represent the industrial sectors from whom emissions of the substances with the new EALs are reported to our pollution inventory

  • emails to manufacturing companies, water companies, interested third parties, academics and non-governmental organisations whom we considered may be interested in our proposals

  • distributing over 800 emails with targeted reminders sent on the 7 December 2020 and the 7 January 2021

We provided the Environment Agency email address EAL[email protected] to facilitate on-line responses to the questions we posed in our consultation document.

We received 11 responses from organisations and groups. The respondents are listed in Appendix A.

3. Summary of main findings and actions we will take

Having considered the responses to our consultation, we intend to introduce the EALs proposed in the consultation by 3 September 2021.

This section summarises the responses we received to our consultation questions and the action we will take as a result of these responses.

Q1. What are your thoughts about our change in thinking on the Excess Lifetime Cancer Risk (ELCR) in deriving the EALs?

There were mixed views in response to this question. Two respondents thought it would be beneficial to see the data and calculations supporting the change in thinking associated with ELCR beyond that presented in the appendices of the consultation.

Another responder supported the use of an ELCR of 1 in 100,000 in the derivation of EALs as they believed this represented a typical targeted risk level for the general public. They added it was also consistent with the current land contamination approach and appropriate for the chemicals under consideration.

However this was countered by a response which suggested that EALs should be derived using an ELCR of 1 in 1,000,000, which had been proposed in our previous guidance in 2012, because:

  • other international organisations such as the European Union (for example, REACH) and the United States Environmental Protection Agency use an ELCR of 1 in 1,000,000

  • the total ELCR for an individual member of the public from all sources and substances may be significantly greater than the ELCR for a single substance

  • there is significant uncertainty in the calculation of the ELCR and a precautionary approach was advisable

The response added that those exposed to emissions controlled by these EALs may be both:

  • unaware of the substances and risks to which they are being exposed

  • unable to limit their exposure to these substances even if they wished to do so

A number of comments made in response to Q1 were not directly related to the question on ELCR. We have provided feedback on these as follows:

  • one respondent highlighted the 3 orders of magnitude reduction in the EAL for naphthalene as particularly challenging and found that the approach for the derivation of the EAL for naphthalene is inconsistent with that applied for benzene – see Q9

  • another respondent asked for the Environment Agency to confirm that there are viable and accepted methodologies for monitoring the new lower EAL concentrations to an appropriate level of accuracy – see Q9

  • a request was made to see the data which have been utilised and the calculations associated with the change in thinking associated with ELCR beyond what is presented in the appendices, in particular as some of the EALs for specific pollutants have decreased by several orders of magnitude – see Q6

Our response

To determine the new and amended EALs we have used an ELCR of 1 in 100,000.

It is noted that in the first version of the methodology published in 2012 we used a default ELCR of 1 in 1,000,000 for substances with sufficient data from human studies. However, following a further review of this methodology, we have opted to apply a default ELCR of 1 in 100,000 in this consultation and all future derivations.

For compounds which are genotoxic and carcinogenic and for which there are no mechanistic data to suggest a threshold for carcinogenicity, or for substances where no mode of action or threshold for effect has been identified, it is currently considered prudent to assume that no threshold for adverse effect exists.

The current UK approach is to reduce exposure to these chemicals to ‘as low as reasonably practicable’ and to apply the management of risk individually to each substance and source.[footnote 1]

An ELCR or 1 in 100,000, derived from relevant human studies,[footnote 2] is considered representative of a minimal risk to human health. This view was subsequently reiterated by the Department for Environment, Food and Rural Affairs in 2014 and is representative of government thinking as to what constitutes minimal risk.[footnote 3] This is broadly consistent with the derivation of limit and target values under the Ambient Air Directive.

The methodology behind ELCR applies to non-threshold carcinogens with sufficient human data, for example vinyl chloride. For other substances, such as naphthalene, which is a threshold carcinogen, ELCR is not relevant.

Q2. Which of the current substance EALs that we are proposing to change do you routinely use to assess the impact of your proposed emissions in support of permit applications?

This question produced responses which varied from nothing at all, to one response listing 10 of the 12 substances. This reflects the variety of raw materials used by industries.

One respondent suggested that substances used by operators of carbon capture plants are likely to be project-specific and hence perhaps a response from individual operators or developers would be more appropriate. However, they concurred that, as a large majority of post-combustion carbon capture plants are based on the use of amine technology, mono-ethanolamine (MEA) and N-nitrosodimethylamine (NDMA) would likely be the most relevant chemicals listed for those operators and developers.

Another response identified NDMA as the only substance of interest.

Our response

The answers provided suggest that the revised EALs will be routinely used by some sectors. We acknowledge the response regarding the carbon capture sector, stating that the EALs for MEA and NDMA represent a good starting point. See also Q7 for responses on the question of future EAL work.

Q3. We are planning to use the new methodology to revise existing EALs for other substances in the future. To help us prioritise our work please list any other substance EALs from the GOV.UK list that are relevant to your permit applications.

This question prompted a variety of responses. One respondent identified formaldehyde, acetaldehyde and ammonia. Two further respondents listed a number of heavy metals and volatile organic compounds associated with the steel and energy from waste industries.

Our response

We welcome the identification of substances important to industrial operators. As part of our ongoing review of EALs we will consider the potential for prioritising the substances identified, as well as other relevant substances.

Q4. Please provide any information regarding the speciation, concentration or content of stack emissions from carbon capture plants, or other information that you think may help us in further development work on EALs for nitrosamines.

The responses to this question varied from ‘no comment’ to detailed responses, supported by a series of published references.

One respondent suggested that the use of specific solvents, and their development by technology manufacturers, is evolving rapidly and different technology suppliers will likely develop and use different formulas to increase the efficiency of the plant.

They added that research has indicated the speciation of amines, and specifically nitrosamines, and their longevity in the atmosphere may be limited to minutes or tens of minutes due to photolytic degradation.

A separate respondent identified the complexity of trying to predict and model the speciation of amines once they have been emitted to the atmosphere, this was also mentioned by a respondent to Q9.

Another respondent noted that research and development into the application of carbon capture to cement production plants is ongoing, for example at plants in Norway and Belgium. However, they reported there are still significant technological and financial barriers to overcome before carbon capture is installed at all operational cement plants in England. It is therefore too early to provide any definitive information on the expected stack emissions.

The respondent also noted that any additional abatement required would add to the already heavy cost of installing carbon capture to decarbonise the cement industry. This point is addressed in Q5.

Furthermore, the respondent queried whether appropriate abatement technologies exist for reduction of nitrosamine emissions.

Monitoring of emissions from point sources and in the environment was identified as an area of concern. This is addressed in our response to Q9.

Our response

Although the technology is relatively new, there are publications which give examples of suitable abatement plant for carbon capture systems, providing initial insights on expected emitted amine species. Guidance includes the recently published Environment Agency post carbon capture best available techniques (BAT) guide,[footnote 4] the Scottish Environment Protection Agency review of amine emissions from carbon capture systems[footnote 5] and the soon to be published Environment Agency recommendations for the assessment and regulation of impacts to air quality from amine-based post-combustion carbon capture plants.

Q5. Please provide an estimate of the financial costs of the proposed EAL changes on you or your sectors operations, supported by cost data, to include a choice of alternative substance if relevant.

Only one response made a specific mention of a potential cost implication, the remaining responses tended to provide more qualitative comments rather than quantitative answers.

One respondent, when referencing the proposed change to the short-term benzene EAL, stated that operators may be required to replace vent gas scrubber fluid more frequently or increase the height of the vent stacks (or both), and that there would be additional costs associated with these requirements.

Another respondent noted that some of the regulated substances emitted during cement production occur naturally within the limestone and other raw materials, rather than being created as part of the manufacturing process. They advised that it was not possible to remove such substances prior to their use. Furthermore, they pointed out that there is no abatement technology or BAT for dealing with some of these emissions, for example those of naphthalene, and this needs to be recognised in any proposed changes to environmental regulation.

A further respondent believed that the issue of costs will be project-specific and the costs of the proposed EAL changes would be best answered by individual operators or developers.

An additional observation suggested the new EAL for nitrosamines might require more costly design of emission control and monitoring systems for 700MW Combined Cycle Gas Turbines with capture rates of 2 million tonnes per annum (mtpa) carbon dioxide, than designs currently used for coal-fired power plants with capture rates of around 1 mtpa CO2.

A response to Q4 noted that any additional abatement required would add to the already heavy cost of installing carbon capture to decarbonise the cement industry.

One respondent raised an additional point regarding the availability of ambient baseline concentrations for carbon capture related substances, coupled with the uncertainty regarding an effective method to obtain baseline information. We address this in Q9.

Our response

The one respondent who provided an estimate of cost implications was particularly concerned about the lowered EAL for naphthalene, suggesting this could have significant cost repercussions for their particular sector.

Permitted emissions of poly aromatic hydrocarbons (PAHs), of which naphthalene is one, from industrial processes continue to reduce. For example, the Best Available Technique Reference (BREF) document for ‘surface treatment using organic solvents’[footnote 6] sets an associated emission limit (AEL) value for point source releases at 1mg/m3 (1,000ug/m3) for PAHs, of which naphthalene is one of 17 listed substances. Therefore an EAL of 3ug/m3, as a daily average concentration, although significantly lower than current, should be readily achievable by most sectors, given the lowering of stack emission limits.

With regards to the concern raised about additional, unspecified, costs associated with the proposed change to the short-term benzene EAL, it should be noted that the (BREF) document for ‘common waste gas management and treatment systems in the chemical sector’, which is currently in draft,[footnote 6] sets an AEL value for point source releases of benzene at <0.5 - 1mg/m3. Moreover, current guidance on GOV.UK for both the ‘production of large organic chemicals’ and the ‘speciality organic chemicals sector’ set an emission limit value for benzene at 5mg/m3.[footnote 7] These regulation-driven new limits on benzene emissions may require operators to invest in upgrading abatement plant or increasing the height of the emission point (or both). The changes would inevitably reduce process contributions to the environment, thus meeting the new benzene EALs without additional spend. We note the guidance is in draft and that the proposed AEL could change before publication, moreover, the BREF would need to be incorporated into UK BAT which could result in the setting of a different AEL BREF range. However, we expect limits on point source emissions to reduce from current levels.

In response to a concern raised by a separate respondent relating to naphthalene, we reviewed data from the Pollution Inventory in 2019. There were 3 sites identified with naphthalene emissions above the reporting threshold. We concluded that using the proposed EAL of 3 μg/m3 as a daily average concentration, all 3 sites would have been screened out from detailed assessment using H1, our risk assessment tool applied to permit applications. Thus we do not expect the new EAL for naphthalene to have a significant effect on the permit requirements for the sector.

Q6. What are your thoughts on our proposed timing for the implementation of the new EALs?

A number of respondents expressed concern over implementing the new or revised EALs now. One respondent stated there were significant challenges facing industries and consultancies due to Brexit and COVID-19 and pointed to delays in permit determinations.

Two responses suggested that the new or revised EALs be introduced when sector reviews are carried out. We note that such reviews may operate on an 8-year cycle.

One respondent stated that they consider REACH data to be the most valid when determining EALs, and that data more than 5 years old should not be higher up in the hierarchy than more recent data.

A concern was also raised that the chemical dossiers provided in Appendix 1 of our consultation document provide little justification for proposing the EALs, and requested clearer information on the methods used through which EALs have been proposed.

Our response

The timing for implementation is based on our duty to ensure that new or existing plant, which is subject to new investment, control emissions to air such that the impacts on the environment are within the new standards. Achieving this outcome would be consistent with the use of BAT. Consistent with supporting economic growth, we also believe it is appropriate that, for plants which are not improved through new investment, such plants should be subject to the new standards when the sector in which the plant operates is subject to a review of its environmental performance. This is an opportunity for us to consider the techniques being used at the time of the review to ensure that BAT is adopted in order to minimise emissions and thereby protect human health. Sector reviews usually happen on an 8-year cycle.

The proposed new or amended values have been developed in consultation with colleagues at PHE. The purpose of the new or updated EALs is to take account of the latest evidence on the toxicity of these substances to human health and to reduce potential impacts on public health.

A distinction needs to be made between ‘data’ and ‘opinion’. REACH opinions may have been made in the last 5 years, but they may have also used much older data, for example toxicological studies that are 5, 10, or even 20+ years old. The date of an opinion is important, especially if it contains new underlying data or an important reinterpretation of the existing data. Our process seeks to review the data and the opinion on its own merits.

Finally, regarding the level of information on how we determined the new EALs in our summary dossiers, we balanced the need to provide succinct information for each substance with the detail needed to address questions that might be raised by toxicologists and other public health specialists. We are open to providing additional detail on the dossiers for specific substances, starting with naphthalene and benzene.

Q7. Please tell us of any substances, for which we do not currently have an EAL on the GOV.UK website, for which you would like to see an EAL developed.

Of the 3 responses received to this question, all suggested that our focus should be on substances relating to carbon capture. One suggested that the use of amine solvents meant that our focus on developing an EAL for MEA and NDMA was appropriate, whilst another went further and identified a series of individual chemicals relating to degradation products of MEA and other similar solvents.

Our response

There was support for our development of new EALs for MEA and NDMA. We will hold further discussions with operators, trade associations, and other organisations to identify other key substances. Operators are required to identify chemicals of concern during permit applications and may propose guidelines for their assessment if an EAL has not yet been published.

Q8. What role do you think industry should play in proposing new values?

A range of views were expressed in response to this question. Some thought that if industry found the new EALs unachievable, there needs to be a public debate before the new values were introduced. The focus of the debate would be the benefits provided by the industry against the air pollution risks.

Other comments supported the need for a collaborative approach between the regulator and the operators to ensure that achieving new or amended values did not impose a disproportionate financial burden on the operator and that the Environment Agency regulate in a pragmatic and proportionate manner based on the available scientific evidence. Others thought plants should be allowed to operate and provide benchmark data to enable the impacts to be determined before any standards were introduced. They went further to suggest that new standards may not be applicable or necessary.

Our response

The Environment Agency recognises the need for new EALs to be introduced, or existing EALs to be updated, to protect the environment and human health from potentially harmful emissions.

We welcome the support for public consultation in development of new or amended EALs, and we will continue to work with operators to find a set of values that protects human health whilst at the same time recognising our role in supporting growth of the economy.

Q9. Please tell us if you have any further comments on any of the information presented in our consultation and provide as much information as possible to support your answer.

We received 7 responses to this question.

Comment

One respondent believed that a key aspect associated with the development of new EALs is the monitoring regime which would need to be put in place in order to demonstrate compliance. They went on to say there are no known Monitoring Certification Scheme (MCERTS) approved methods, or approved continuous emissions monitoring systems (CEMs) which could be used to monitor specific amines or a suite of amines. Furthermore, the respondent noted that in Appendix 2 of the consultation document the Environment Agency identifies Fourier transform infrared analysers (FTIR) as a possible analytical technique. But they felt there was little evidence presented of its accurate use in identifying amine species and indeed to the levels of accuracy required to comply with Environment Agency standards.

Our response

To date no certified CEMS for amine monitoring from carbon capture plant has been developed. This is in part because there has been no commercial reason for them to be developed and then certified. The same applies to periodic monitoring. We believe that stack monitoring companies do have the ability to carry out required monitoring but there will be some development necessary to refine measurement methods. We will consider the need to develop British Standards for CEMs and periodic monitoring. FTIR was referenced as an option because it has been used in this area of work before, although only on limited occasions. More work is needed to establish how suitable it will be.

Comment

One respondent asked for further information to better understand the derivation of the new EALs for MEA and NDMA. They felt that there was insufficient detail in the summary dossier to explain the decisions made and asked that more information be provided to explain the differences between our approach and that used for the proposed ‘derived no-effect level’ in the REACH dossier.

Our response

In the summary dossier issued as part of the consultation, we balanced the need to provide succinct information on the evidence evaluated for each substance with the detail needed to address questions that might be raised by toxicologists and other public health specialists. As requested, Appendix C includes longer and more comprehensive summaries of the toxicological evidence for MEA and NDMA, which explains how the evidence was used in the derivation of the short- and long-term EALs. These dossiers were shared and discussed with PHE. They also serve as examples to third-parties including permit applicants of how to apply the approach developed in 2012 to the evaluation of new substances.

Comment

One respondent mentioned that the Environment Agency risk assessment guidance advises that “If you release volatile organic compounds into the air and do not know what all the substances in them are, treat them all as 100% benzene in your risk assessment”. And that a reduction in the short-term EAL for benzene will significantly increase the number of assessments requiring further modelling (or additional monitoring work to speciate the emissions) where this default assumption of 100% benzene has been used.

Our response

Our guidance goes on to say “If you want to treat them as something else, you’ll need to explain why”. We will assess site specific options, for example use of process data, to better understand emissions at the permit application stage.

Comment

One respondent raised additional points in response to Q1, not associated with the question on ELCR, which we address here. The respondent noted that the EAL for naphthalene was to be reduced by 3 orders of magnitude; and questioned it being set on, in their opinion, indoor air quality guidance. The same respondent also stated there was an inconsistency in the approach for the setting of the EAL for naphthalene compared to that for benzene.

Our response

Although the EAL for naphthalene is based on an independent toxicological review, the outcome is consistent with the indoor air quality guidance.

The short-term EAL for benzene is based on toxicological data from short-term or acute exposures. The short-term EAL is applicable because application of the long-term EAL alone could allow short-term daily exposures to exceed the short-term EAL over the year. That is, compliance with the long-term EAL might not prevent short-term exposures that pose a risk to public health.

There is no short-term EAL for naphthalene because there is insufficient evidence on the risks to health from short-term or acute exposures. The long-term EAL is based on toxicological data from long-term or chronic exposures. Our independent review reached the same conclusion as the indoor air quality guideline, but it is not based on it.

Comment

A separate respondent also added an additional point in response to Q1 which was not associated with the question on ELCR, which we address here. The respondent stated it would be beneficial for the Environment Agency to confirm that there are viable and accepted methodologies for monitoring the new low EAL concentrations to an appropriate level of accuracy.

Our response

To date there has been no commercial reason for the development of ambient air quality monitoring systems for the low concentrations being proposed, and the new EALs may in some cases be at the limit of the current level of detection of existing equipment. As technology becomes embedded and monitoring requirements become established, these issues will be addressed by new methodology and equipment.

Comment

One respondent highlighted that, where the US Minimal Risk Levels (MRLs) have been used in developing EALs, the shortest end of the applicable time period has been selected, that is for acute (1 to 14 days) exposures, the US values have been applied to give a 24h mean EAL, for example benzene, vinyl chloride. This may result in EALs that are too challenging at least in the short term.

Our response

Several short-term EALs have been based on acute MRLs proposed by the Agency for Toxic Substances and Disease Registry (ATSDR), who define exposure duration as 1 to 14 days. This is to distinguish the types of studies and endpoints reviewed compared to longer exposures of up to a year or more. It is not appropriate to conclude that a different value or decision would be made on a duration of 1 day or 14 days. Acute exposures are consistent with exposure periods considered for short-term EALs – although they are longer than workplace exposure limits (WELs). Short-term EALs protect public health from the adverse effects of higher emissions for short periods where they would not otherwise be prevented through application of the long-term EAL.

Comment

One respondent raised an additional point in response to Q5, which we address here. The respondent was concerned about the availability of ambient baseline concentrations for carbon capture-related emissions, coupled with the uncertainty regarding an effective method to obtain baseline information. The respondent suggested that advice be given on this issue in advance of an application for an environmental permit.

Our response

We would advise applicants to apply for enhanced pre-application advice and guidance at the earliest opportunity to address these issues.

5. Next steps

Once this document is published we will use the new EALs in our regulatory activities. For all new permit applications and for all substantially changed permits, the new values will apply from day one of the new operation. For all existing permits the new values will be implemented when permits are subject to sector review.

The Growth Duty,[footnote 8] applied from 2017 through the Deregulation Act 2015, requires the Environment Agency and other national regulators to have regard to the desirability of promoting economic growth, alongside our other statutory duties. We have included questions in the consultation to help us obtain the necessary information to meet this requirement in relation to the proposed new EALs.

Our technical dossier has reviewed more than the dozen substances included within the 2020 consultation. We are working with colleagues in PHE to finalise proposals on an additional set of new EALs which will feature within a second consultation.

Email us at EAL[email protected] if you wish to be notified of the launch of the second consultation.

Appendix A – respondents

The following responded to the consultation:

  • Atkins

  • BP and NZT Project

  • Carbon Capture & Storage Association

  • Chemical Industries Association

  • CRAIN (Carlisle Residents Against Incinerator)

  • Drax Power Limited

  • Mineral Products Association

  • Pale Blue Dot Energy Limited

  • Shell UK

  • Tata Steel

  • Wood Protection Association Creosote Group

Appendix B – consultation questions

Q1. What are your thoughts about our change in thinking on the Excess Lifetime Cancer Risk in deriving the EALs?

Q2. Which of the current substance EALs that we are proposing to change do you routinely use to assess the impact of your proposed emissions in support of permit applications?

Q3. We are planning to use the new methodology to revise EALs for other existing substances in the future. To help us prioritise our work please list any other substances EALs from the GOV.UK list that are relevant to your permit applications.

Q4. Please provide any information regarding the speciation, concentration or content of stack emissions from carbon capture plants, or other information that you think may help us in further development work on EALs for nitrosamines.

Q5. Please provide an estimate of the financial costs of the proposed EAL changes on your or your sectors operations supported by cost data to include a choice of alternative substance if relevant.

Q6. What are your thoughts on our proposed timing for the implementation of the new EALs?

Q7. Please tell us of any substances for which you would like to see a new EAL developed.

Q8. What role do you think industry should play in proposing new values?

Q9. Please tell us if you have any further comments on any of the information presented in our consultation and provide as much information as possible to support your answer.

References