Foreword
The European regulatory framework for plant protection products has reached a new milestone. On 27 May 2026, the European Commission officially published Regulation (EU) 2026/1120, updating the list of unacceptable co-formulants found in Annex III of Regulation (EC) No 1107/2009. Following a lengthy debate, 12 new substances have been added to the “black-list,” bringing the total number of banned ingredients to 156.
While co-formulants are technically defined as substances that are neither active ingredients nor safeners or synergists, their biochemical “inertia” is often more apparent than real. This update reinforces the EU’s commitment to removing substances with high-risk profiles from agricultural products.
The Selection Criteria: Why These 12?
The inclusion of these substances is based on stringent safety criteria that leave little room for interpretation. The banned co-formulants fall into several high-concern categories:
- CMR Properties: Substances classified as carcinogenic, mutagenic, or toxic for reproduction (Category 1A or 1B), such as Acetaldehyde, Propylene oxide, and 1,4-dioxane.
- PBT and vPvB Profiles: Ingredients that are persistent, bioaccumulative, and toxic, or very persistent and very bioaccumulative. This group specifically includes the siloxanes (D4, D5, and D6) and Bumetrizole.
- Persistent Organic Pollutants (POPs): Such as derivatives of phosphinic acid.
- Unapproved Biocides: Substances not approved for use as preservatives for products during storage (Product Type 6).
The Final List of Prohibited Substances
The 12 substances officially added to the list of unacceptable co-formulants are:
- Acetaldehyde (Ethanal)
- Propylene oxide
- Cumene
- Dodecamethylcyclohexasiloxane (D6)
- Decamethylcyclopentasiloxane (D5)
- Octamethylcyclotetrasiloxane (D4)
- Bumetrizole
- Distillates (petroleum), solvent-dewaxed light paraffinic (with ≥ 3.0% DMSO extract)
- Methenamine 3-chloroallylochloride (CTAC)
- Phosphinic acid, bis(perfluoro-C6-12-alkyl) derivatives
- 1,4-dioxane
- 2-(4-tert-butylbenzyl)propionaldehyde
The “Spared” Substances: What Changed from the Drafts?
An interesting aspect of this regulatory update is the evolution of the debate. Nine substances that were present in early drafts from 2025 were ultimately “spared” and do not appear in the final regulation. This highlights the technical scrutiny and advocacy that occurred during the legislative process.
The substances that appeared in earlier drafts but were not included in the final published regulation are:
- Methenamine (CAS 100-97-0): While its compound, CTAC, was banned, pure methenamine was removed after the first draft.
- Formaldehyde dibenzyl acetal: A formaldehyde releaser present only in the first draft.
- 1,3,5-triazine-1,3,5(2H,4H,6H)-triethanol: Another substance dropped after the initial draft.
- Methanol, 1-(phenylmethoxy)-: Present only in the first version.
- 2-pyrrolidone: This substance survived until the second draft before being excluded.
- Hydrocarbons, C9, aromatics (with cumene content ≥ 0.1%): Removed after the first draft.
- Polydimethylsiloxane: The well-known anti-foaming agent was present in the first draft but was not included in the final ban.
- Acetophenone: Included in both the first and second drafts but ultimately excluded.
- Glutaraldehyde: Present only in the first draft.
The Impurity Threshold
For formulators, a critical technical detail is the management of unintentional impurities. The regulation establishes that an unacceptable co-formulant is tolerated as an impurity only if it remains below 0.1% weight by weight (w/w) in the finished product. For CMR substances, this limit may be even lower if specified by other regulations, provided analytical methods can technically support such detection levels.
Roadmap and Compliance Deadlines
The Commission has set a clear timeline to ensure an orderly transition for the industry:
- 16 June 2028: This is the final deadline for Member States to revoke or modify authorisations for plant protection products containing any of the 12 newly banned substances.
- Grace Periods: Following the revocation of an authorisation, grace periods for stock disposal are strictly limited. Sale and distribution are permitted for a maximum of 3 months, while storage and final use must conclude within 12 months total from the revocation date.
Navigating Regulatory Complexity
At Euregulator, we specialise in defining regulatory strategies that transform complex legislation into clear, actionable technical solutions. We support businesses in managing authorisation processes and performing the essential toxicological and environmental risk assessments required in this changing landscape.
For expert guidance or technical support, please contact us at info@euregulator.eu.
Find out more
Commission Regulation (EU) 2026/1120 of 26 May 2026 Amending Annex III to Regulation (EC) No 1107/2009 of the European Parliament and of the Council by Adding Twelve Co-Formulants Which Are Not Accepted for Inclusion in Plant Protection Products (2026).