Laws relating to in situ generated active substances
Under the terms of the European regulation on biocidal products (BPR; EU 528/2012) that came into force on 1 September 2013, and the Ordinance on Biocidal Products (OBP, 813.12), active substances generated in situ, and the associated precursors, are considered to be biocidal products and are subject to approval.
Nomenclature for in situ generated active substances
The name of in situ generated active substances was amended in step with the new nomenclature for the review program. The new nomenclature for the in situ generated active substances thus clearly defines a precursor/active substance combination and the procedure used to produce the active substance (e.g. active chlorine from sodium chloride by electrolysis). It is therefore important that you use the new names of the in situ generated active substance for the application. More detailed information on in situ systems may be found here.
In situ systems: precursors and in situ generated active solution
Under the new nomenclature the active substance name describes the underlying in situ system that generates the active substance in situ (previously named by the Swiss authorities as the active solution). The technical active substance generated in situ is understood to mean the in situ produced solution. This comprises the pure in situ generated active substance, possible residues of the precursor(s), and if applicable, by-products formed during the in situ reaction. If the solvent (usually water) is not comprised in one of the precursors, then this must be listed in the composition of the technical active substance generated in situ. An example: precursor (e.g. powder) is dissolved in (aquarium) water.
If a precursor for the in situ production of a biocidal active substance is marketed, then pursuant to Art. 2 para 1 let. a OBP the precursor is considered to be the biocidal product subject to approval. If for an in situ system no precursor for the in situ production of a biocidal active substance is marketed (e.g. generation of ozone from the oxygen of ambient air, active chlorine from sea water by electrolysis), then the technical active substance generated in situ is considered to be the biocidal product subject to approval.
Various in situ systems
The various in situ systems consist of one or more precursor(s) and require, if applicable, the use of a device (production procedure such as e.g. electrolysis) to generate the biocidal active substance in situ.
If an in situ system consists of a plurality of precursors, these may be either marketed in individual containers that are packaged together (e.g. two containers that are packaged together with a plastic film), or they may be firmly connected/blended together (e.g. multi-component tabs).
The Swiss authorities have matched the definition of in situ systems to those of the European Chemicals Agency (ECHA). Acids, bases or oxidising agents are now considered as precursors (recommendations BPR – in situ active substances 2017). Previously the Swiss authorities differentiated between precursors and auxiliaries. For the in situ system “chlorine dioxide generated from sodium chlorite by acidification” the sodium chlorite (precursor) was differentiated from the acid (auxiliary). Sodium chlorite and the acid are now considered as precursors and are therefore subject to approval.
Requirements for the application dossier of an in situ system
The applicant must submit to the Notification Authority Chemicals documents on the various components of the in situ system (i.e. precursor[s], if applicable auxiliaries and production procedure) as well as on the technical active substance generated in situ.
Due to the diversity of in situ systems the requirements for the application documents are not standardised. The Swiss authorities have sub-divided the in situ systems into four categories, based on the requirements for the application dossier. These categories are based on the experience so far and may be extended at a later date or, if necessary, amended.
The following categories are differentiated: