Candidates for Substitution and Comparative Assessment
Candidates for Substitution and Comparative Assessment
The Biocidal Products Regulation (BPR) includes specific provisions intended to encourage the substitution of active substances with particular hazardous properties or other characteristics of regulatory concern.
An active substance meeting the relevant criteria can be identified as a candidate for substitution. This does not mean that the substance is prohibited. It does, however, affect both the terms of active substance approval and the assessment of biocidal products containing it.
In particular, products containing a candidate for substitution are subject to comparative assessment when applications for authorisation or renewal are evaluated. The assessment considers whether suitable alternatives are already available that provide a significantly lower overall risk without creating significant economic or practical disadvantages.
Understanding the distinction between candidate-for-substitution status, analysis of alternatives and comparative assessment is therefore important when considering active substance strategy and the future market access of products containing the substance.
What is a candidate for substitution?
Article 10 of the EU BPR establishes the criteria for identifying active substances as candidates for substitution.
An active substance is considered a candidate for substitution if it meets at least one of the specified criteria. These include circumstances where the substance:
- meets one or more of the BPR exclusion criteria but can nevertheless be approved under an Article 5 derogation;
- meets the criteria for classification as a respiratory sensitiser;
- has an acceptable daily intake, acute reference dose or acceptable operator exposure level that is significantly lower than those of the majority of approved active substances for the same product type and use scenario;
- meets two of the criteria for being persistent, bioaccumulative and toxic (PBT);
- gives rise to particular concerns which, when combined with its use patterns, mean that its use could still cause concern even with very restrictive risk-management measures; or
- contains a significant proportion of non-active isomers or impurities.
Candidate-for-substitution status is therefore based on characteristics of the active substance. It is determined during the active substance approval or renewal process.
ECHA – Approval of active substances
EUR-Lex – Regulation (EU) No 528/2012
What does candidate-for-substitution status mean?
Identifying an active substance as a candidate for substitution does not automatically remove it from the market.
The substance can still be approved where it satisfies the applicable requirements of the BPR. However, candidate-for-substitution status has consequences for the regulatory process.
Under EU BPR, approval and each renewal of a candidate for substitution cannot normally exceed seven years. Where the substance also meets one or more of the exclusion criteria and is approved under the applicable derogation provisions, a shorter maximum approval period applies.
The status also has an important downstream consequence: biocidal products containing the active substance must undergo comparative assessment when an application for authorisation or renewal is evaluated.
Candidate-for-substitution status therefore creates a link between the assessment of the active substance and future regulatory decisions affecting products and uses.
Consultation on potential candidates for substitution
Where an evaluating competent authority identifies an active substance as a potential candidate for substitution, the BPR provides for consultation before the approval or renewal decision is finalised.
ECHA normally opens a public consultation to gather information on potential alternatives to the active substance.
The purpose is to establish whether suitable alternatives are available, including alternative active substances and non-chemical approaches.
Evidence submitted may address matters such as:
- the functions and uses of the active substance;
- alternative substances or technologies;
- technical feasibility;
- efficacy;
- risks associated with alternatives;
- availability;
- implementation requirements; and
- economic or practical considerations.
Evidence about alternatives is more useful where it addresses the specific uses and functions concerned rather than simply demonstrating that another substance or technology exists.
Current EU consultations are available from:
ECHA – Consultations on potential candidates for substitution and derogation conditions
Under GB BPR, HSE operates a corresponding consultation process when its evaluation indicates that an active substance meets the substitution criteria.
HSE – Submitting information on potential candidates for substitution under GB BPR
What is comparative assessment?
Comparative assessment operates at the biocidal product level.
Under Article 23 of the EU BPR, the competent authority must carry out a comparative assessment when evaluating an application for authorisation or renewal of a biocidal product containing an active substance that is a candidate for substitution.
The purpose is to determine whether the product should continue to be authorised for the uses concerned when a suitable alternative is already available.
This is different from deciding whether the active substance itself should be approved.
Candidate-for-substitution status is established at active substance level.
Comparative assessment considers the implications at product and use level.
What does the comparative assessment consider?
For the uses covered by the application, the authority considers whether another authorised biocidal product or a non-chemical control or prevention method already exists which:
- presents a significantly lower overall risk for human health, animal health and the environment;
- is sufficiently effective;
- presents no other significant economic or practical disadvantages; and
- does not undermine the chemical diversity needed to minimise the development of resistance in the target harmful organism.
These conditions need to be considered together.
The existence of another authorised product is therefore not, by itself, sufficient to demonstrate that substitution should occur.
An alternative may have different efficacy, operating requirements, application methods, costs, availability or other practical implications. These factors may need to be understood before it can be concluded that the alternative provides a suitable substitute for the particular use.
ECHA – National authorisation and mutual recognition
What can happen following comparative assessment?
Where the requirements in Article 23 are met, the competent authority may be required to prohibit or restrict the making available on the market or use of the product containing the candidate for substitution.
The outcome can therefore apply to particular uses rather than necessarily resulting in the removal of the product in every application.
This makes the definition of the use particularly important.
An alternative may be suitable for some uses but not others because of differences in:
- target organisms;
- required efficacy;
- conditions of use;
- application technology;
- materials or processes involved;
- user groups;
- resistance-management requirements; or
- economic and practical constraints.
Comparative assessment should therefore be based on the circumstances of the uses being considered rather than a generic comparison between two products.
Technical performance and efficacy
A potential alternative must be sufficiently effective for the relevant use.
This requires consideration of what the biocidal product is expected to achieve under realistic conditions.
Relevant factors may include:
- target organism;
- required level of control;
- speed and duration of action;
- treatment frequency;
- environmental or operating conditions;
- compatibility with materials and processes;
- application method; and
- consequences of reduced performance.
Where products are used in technically specialised applications, evidence from users can be important in establishing whether an apparent alternative can actually perform the same function.
Comparing risks
Comparative assessment requires an alternative to offer a significantly lower overall risk for human health, animal health and the environment.
The comparison therefore needs to consider the relevant risks of the products or methods being compared rather than relying solely on one hazard characteristic of their active substances.
Depending on the circumstances, differences in exposure, application method, dose, frequency of use and risk-management requirements may all be relevant.
The comparison should also avoid assuming that substitution necessarily removes risk. A potential alternative may introduce different hazards or exposure patterns that need to be taken into account.
Economic and practical disadvantages
The BPR explicitly recognises that economic and practical consequences matter when deciding whether an alternative is suitable for substitution.
These considerations may include:
- differences in product or treatment costs;
- changes in application frequency;
- additional labour requirements;
- equipment or infrastructure changes;
- reformulation;
- process changes;
- additional maintenance;
- implications for production efficiency;
- product or material performance;
- supply and availability;
- implementation timescales; and
- other operational constraints.
The relevant question is not simply whether the alternative costs more.
The assessment should consider whether the economic or practical disadvantages are sufficiently significant in the context of the particular use.
Where wider economic or societal consequences are material, additional socio-economic evidence may be relevant.
Related RPA page: Socio-economic Analysis for Biocides
Resistance and chemical diversity
Comparative assessment must also consider whether there is sufficient diversity among available active substances to minimise the development of resistance in the target harmful organism.
This is particularly important where repeated reliance on a limited number of modes of action could reduce the effectiveness of available control methods over time.
An alternative that appears suitable when considered in isolation may therefore need to be assessed within the wider context of resistance management.
This illustrates why comparative assessment is not simply a comparison of the hazard profiles of two substances or products.
Analysis of alternatives and comparative assessment
Analysis of alternatives (AoA) and comparative assessment are related but should not be treated as the same process.
An AoA can provide structured evidence on potential substitutes for an active substance, including their technical feasibility, efficacy, availability and economic or practical implications.
This information can help establish the wider alternatives landscape surrounding an active substance.
Comparative assessment, however, is a specific regulatory assessment under Article 23 concerning a biocidal product containing a candidate for substitution and the uses for which authorisation or renewal is sought.
Evidence developed through an AoA can therefore inform questions relevant to comparative assessment, but the scope and regulatory purpose of the two assessments are different.
Related RPA page: Analysis of Alternatives for Biocidal Active Substances
ECHA’s framework guidance is available here:
Comparative assessment under GB BPR
GB BPR also provides for candidates for substitution and comparative assessment.
HSE identifies active substances as candidates for substitution where they meet the applicable criteria under Article 10 of GB BPR.
Products containing those substances must undergo comparative assessment as part of the evaluation of relevant applications for authorisation or renewal.
HSE describes comparative assessment as an assessment of the risks and benefits of a biocidal product compared with other authorised biocidal products, non-chemical means of control and prevention methods.
As under EU BPR, the assessment considers the availability of alternatives, their risks and effectiveness, economic and practical disadvantages and the need to maintain sufficient chemical diversity to minimise resistance.
HSE’s current work on anticoagulant rodenticide renewals provides a practical example of comparative assessment being used to examine available chemical and non-chemical alternatives for particular biocidal uses.
HSE – Biocides glossary: candidates for substitution and comparative assessment
HSE – Submitting information on potential candidates for substitution under GB BPR
Evidence from users and affected sectors
Comparative assessment can depend on information that is not fully captured in regulatory dossiers or product labels.
Manufacturers, professional users and affected sectors may hold evidence concerning:
- how products are used in practice;
- performance requirements;
- alternative products already tested;
- limitations of non-chemical methods;
- resistance-management needs;
- operational constraints;
- supply and availability;
- costs of changing treatment methods; and
- consequences of losing particular uses.
This evidence can be important where the suitability of an alternative depends on circumstances that differ substantially between sectors or applications.
Evidence should be specific and documented. Statements that an alternative is unsuitable are more informative when the technical, practical or economic reasons can be demonstrated.
Preparing for comparative assessment
Where a product contains an active substance that is, or may become, a candidate for substitution, it can be useful to consider comparative-assessment issues before the product authorisation or renewal reaches the decision stage.
This can involve:
- establishing the precise uses that may be assessed;
- identifying relevant authorised products and non-chemical alternatives;
- assessing their efficacy and technical feasibility;
- examining comparative risks;
- considering economic and practical disadvantages;
- assessing resistance-management implications;
- gathering evidence from relevant users and sectors;
- identifying important uncertainty and evidence gaps; and
- ensuring conclusions are supported by evidence relevant to each use.
Early analysis can also identify where more detailed analysis of alternatives or socio-economic evidence may be needed.
How RPA can contribute
Candidates for substitution and comparative assessment can require regulatory, scientific, technical and economic evidence to be brought together.
RPA can contribute through:
- reviewing the regulatory status and implications of candidate-for-substitution identification;
- analysing potential alternatives;
- assessing technical and practical feasibility;
- reviewing scientific and regulatory evidence;
- gathering evidence from affected users and sectors;
- assessing economic and practical implications;
- undertaking socio-economic analysis where relevant;
- identifying evidence gaps and uncertainties; and
- developing evidence to support regulatory and market-access decisions.
The scope of the work should reflect the specific substance, product, uses and regulatory decision rather than assuming that the same evidence is appropriate for every comparative assessment.
Official guidance and legislation
ECHA – Approval of active substances
ECHA – Consultations on potential candidates for substitution and derogation conditions
ECHA – National authorisation and mutual recognition
HSE – Submitting information on potential candidates for substitution under GB BPR