Biocidal Products Regulation: In-Can and Dry-Film Preservatives in Coatings

What the Biocidal Products Regulation Is and Why It Exists

The BPR replaced the earlier Biocidal Products Directive 98/8/EC to close a structural weakness: under the Directive, member states implemented biocide control unevenly, and the burden of proving safety was not consistently placed on industry. The Regulation applies directly in every member state without national transposition, which removes much of that divergence. Its purpose is to ensure that biocidal products placed on the EU market are effective against the target organisms and acceptably safe for human health and the environment, assessed on a common evidence base. Preservatives in paint fall squarely inside this purpose because they are deliberately added to kill or suppress microorganisms.

The Regulation works on two tiers that operate in sequence. First, each active substance is assessed and either approved or not approved at EU level, separately for each product type in which it is used. Second, a biocidal product containing an approved active can be authorised — nationally, through mutual recognition between member states, or through a single Union authorisation. Only after both tiers are satisfied can the product be sold and used lawfully. For coatings, the practical consequence is that the preservative your supplier sells you must clear both hurdles for the exact function you rely on, and the finished paint inherits obligations from the treated-article provisions layered on top.

Scope: Who It Applies To and Which Products Are Covered

The BPR reaches further into the coatings supply chain than many formulators expect, because it captures not only the companies that make biocides but also the companies that put them into other products. A paint manufacturer that never touches a drum of raw active substance still carries obligations the moment it adds an authorised preservative to a batch. Understanding which role you occupy determines which obligations apply and which exemptions you can rely on.

• Active substance manufacturer or supplier — must be listed under Article 95 for the relevant product type for that active substance to be lawfully used in products on the EU market
• Biocidal product supplier — the company that formulates and places the preservative product (for example an isothiazolinone or IPBC blend) on the market, and that holds the product authorisation and its Summary of Product Characteristics
• Treated article producer — the paint or coating manufacturer that incorporates the preservative into the finished coating; bound by Article 58 to use only approved or under-review actives and to apply treated-article labelling where a biocidal claim is made
• Importer of treated articles — a company bringing coatings into the EU from outside must verify that every biocide used would be permitted for an EU-made equivalent, and remains responsible for treated-article labelling
• Downstream user and distributor — must keep and pass on the Safety Data Sheet, respect the authorised conditions of use, and provide biocidal-treatment information to consumers on request within 45 days

On the product side, the two product types that matter for coatings are defined in Annex V to the BPR. PT6 is preservatives for products during storage, covering in-can protection of wet paint, and PT7 is film preservatives, covering protection of the dry coating film. Adhesives, fillers and construction chemicals that are water-based fall under the same two product types. If your coating makes no biocidal claim about protecting the surface it is applied to, you are dealing with PT6 and PT7 as preservation functions only — not a disinfectant or antifouling product, which are separate product types with their own regimes.

Key Requirements: PT6, PT7, and Treated Articles

The core obligations for a coating manufacturer cluster around three questions: is the active substance approved for the function I am using it for, is the preservative product authorised for that use at the concentration I need, and have I met the treated-article rules for the finished paint. Each question has a different owner in the supply chain, but the paint manufacturer carries the residual risk if any link fails.

Active Substance Approval by Product Type

An active substance is approved separately for PT6 and for PT7, and approval for one does not imply approval for the other. Benzisothiazolinone and methylisothiazolinone are widely used for PT6 in-can preservation, while film protection typically relies on iodopropynyl butylcarbamate, octylisothiazolinone, dichlorooctylisothiazolinone, zinc pyrithione, and triazine actives such as terbutryn for algal control. Approval can come with restrictions — a maximum concentration, a ban on consumer products, or mandatory risk mitigation such as encapsulation to limit leaching from facades. The current status of each active is published on the ECHA website and changes as the Review Programme and classification decisions progress.

Product Authorisation and the Summary of Product Characteristics

The preservative product itself must hold a national authorisation, a mutual-recognition authorisation, or a Union authorisation for PT6, PT7, or both. That authorisation is defined by its Summary of Product Characteristics, which sets the permitted product types, the maximum in-use concentration, the permitted user categories, and any required precautions. A paint manufacturer must dose the preservative within those limits; exceeding the authorised concentration makes the finished paint non-compliant even though the biocide itself is authorised.

Treated-Article Obligations Under Article 58

A coating containing a preservative to protect the coating itself is a treated article. It may only be treated with biocidal products whose active substances are approved for the relevant product type or are still under review in the Programme. Where the coating is marketed with any claim about its biocidal properties — a mould-resistant or algae-resistant facade paint, for example — Article 58(3) requires specific labelling: a statement that the article contains biocidal products, the biocidal property claimed, the name of every active substance, the name of any nanomaterial, and relevant use instructions and precautions. Getting the classification and the label right the first time is far cheaper than a market withdrawal later.

Testing and Documentation Requirements

Most of the heavy data generation under the BPR falls on the active substance and biocidal product suppliers, not on the paint manufacturer. Their dossiers must demonstrate efficacy against the target organisms, characterise human health hazards, and quantify environmental fate and effects, including emission and leaching from treated surfaces for PT7. A coating formulator does not repeat that work, but it must hold enough documentation to prove its own finished products are compliant treated articles and that its preservative dosing sits inside the authorised envelope.

• Preservative authorisation evidence — a current copy of the Summary of Product Characteristics for each preservative used, for each EU market of sale, confirming PT6 or PT7 coverage and the maximum authorised concentration
• Active substance status record — documented confirmation that every active in every preservative is approved or under review for the relevant product type, with the review identifier and any use restrictions noted
• Article 95 confirmation — evidence that the active substance or product supplier is listed under Article 95 for that substance and product type
• Efficacy data for the finished coating — challenge testing for wet-state preservation, and for film-protected products, standardised fungal and algal resistance testing such as EN 15457 and EN 15458 or the corresponding ASTM methods, to support any biocidal claim made on the label
• Safety Data Sheet and label consistency — an SDS for the finished coating that reflects the CLP classification driven by the preservative content, and a label whose treated-article statements match the claim actually made
• Consumer information procedure — a documented process to answer a consumer request about the biocidal treatment of a product within 45 days, free of charge

Keeping this evidence current is a live task, not a launch-day file: an active moving to non-approval, or an authorisation being varied, changes what your documentation must say. Treat the preservative dossier as a controlled document with a scheduled review.

Step-by-Step Compliance Pathway for Coating Formulators

BPR compliance for a coating manufacturer is a continuous management process rather than a one-time certificate. It is triggered again every time a preservative is changed, a new market is added, or ECHA publishes a decision on an active substance you use. The sequence below gives a practical framework for reaching and holding a compliant position across the product portfolio.

1. Map the preservative function for every product. For each formulation, record whether it needs PT6 in-can protection, PT7 film protection, or both, and identify the preservative product used for each function.
2. Confirm active substance approval status by product type. For every active in every preservative, check the ECHA active substance list for PT6 and PT7 separately, and record whether it is approved, approved with restrictions, under review, or not approved.
3. Verify product authorisation for each market of sale. Obtain the Summary of Product Characteristics for each preservative in each EU country where the coating is sold, and confirm the product type coverage and the maximum authorised in-use concentration.
4. Check your dosing against the authorised concentration. Compare the preservative loading in each formulation against the SPC limit, and reformulate or re-dose where the loading exceeds the authorised maximum.
5. Apply the treated-article rules. Confirm every active used is approved or under review, and where the coating carries a biocidal claim, build the Article 58(3) label with the contains-biocidal-products statement, the claimed property, and all active substance names.
6. Align the Safety Data Sheet and CLP label. Ensure the finished coating SDS and hazard label reflect the classification contribution of the preservative, including skin sensitisation statements where isothiazolinones are present above the relevant limits.

Realistic Timeline and Cost Expectations

For a paint manufacturer that buys authorised preservatives rather than seeking its own product authorisation, BPR compliance is a moderate ongoing overhead rather than a major project. Establishing a first full compliance review across an existing portfolio — mapping preservative functions, checking active substance status, gathering Summaries of Product Characteristics for each market, and aligning labels — typically takes two to four months for a mid-sized range, most of it internal time. The larger cost variable is not the audit but the response to a negative regulatory decision.

The main cost categories are internal regulatory and technical staff time for the portfolio review and for ongoing monitoring, external consultancy where BPR expertise is not held in-house, supplier engagement to obtain current Summaries of Product Characteristics for every market of sale, and reformulation and re-testing where an active substance is restricted or refused. Where a company seeks its own biocidal product authorisation — relevant if it blends or repackages preservatives, or makes strong biocidal claims — the dossier, national fees, and assessment period run over several years and are a different order of investment.

Reformulation is the cost that derails budgets. If a film preservative active receives a negative opinion, replacing it means screening alternatives, running fungal and algal resistance testing over realistic exposure periods, revalidating exterior durability, and updating labels and Safety Data Sheets across every market — a programme that can run twelve to twenty-four months from decision to compliant relaunch. Building a validated alternative into the formulation platform before the decision lands turns a crisis into a planned changeover.

Common Mistakes Coating Manufacturers Make — and How to Avoid Them

The BPR failures seen most often in coatings are not deliberate non-compliance. They are structural gaps where a process was never designed to catch a specific obligation, and they usually surface during a customer audit, a distributor query, or a border inspection. Knowing the recurring patterns lets a formulator close them before they become an enforcement issue.

• Treating PT6 approval as covering PT7 — an active approved for in-can preservation is not automatically approved for film protection; each function must be checked against its own product type, and a preservative marketed for both must be authorised for both
• Dosing above the Summary of Product Characteristics limit — the authorisation protects the use only within its stated maximum in-use concentration; a recipe that carries more preservative than the SPC allows makes the finished coating non-compliant
• Ignoring treated-article labelling when a claim is made — marketing a facade paint as mould-resistant is a biocidal claim, and it triggers the full Article 58(3) label, including naming every active substance; a claim on the website or a technical data sheet counts
• Assuming imported coatings are outside scope — a coating imported into the EU must only contain biocides that would be permitted for an EU-made equivalent, and the importer carries the treated-article obligations, including labelling
• Overlooking isothiazolinone sensitisation classification — methylisothiazolinone and related actives carry stringent skin sensitisation limits that flow into the CLP classification and labelling of the finished paint, independent of the BPR authorisation
• Losing track of the Review Programme — actives still under review are lawful to use now, but a decision can arrive with a phase-out period measured in months; without a monitoring routine and a reformulation reserve, that decision becomes a supply interruption

For background on why water-based systems depend so heavily on preservation, the Global Formulation guide to waterborne versus solvent-borne paints covers the microbiological vulnerability of aqueous formulations, while the paints and coatings formulation guide sets out the additive categories involved, and the anti-graffiti coatings guide illustrates how surface-active functional claims interact with regulation. Official BPR guidance is maintained by ECHA, and the consolidated legal text is on EUR-Lex as Regulation (EU) No 528/2012.