Cybutryne; 2-Methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazin; formula: C11H19N5S; CAS Registry Number: 28159-98-0
Structure of Irgarol
Source: PubChem
Identifier: CID 91590

Biocide used in antifoulings

Irgarol (Cybutryne) is a very effective herbicide which blocks the photosynthesis of plants. It is mainly used as active ingredient in antifouling coatings for hulls and underwater constructions.
Since the 1980s Irgarol has increasingly been used as substitute of the antifouling active ingredient Tributyl tin (TBT) which is banned in the European Union since 2003. Until 2011 it was also allowed to use Irgarol as an algicide for coatings of outer facades.

Since 2004 the German Umweltbundesamt (Federal Environment Agency) has been carried out extensive mesocosm studies in its test plant of artificial streams and ponds and has been analysed nationwide water samples for Irgarol. These results found entrance into the derivation of the environmental quality standards (EQS) for Irgarol in the context of the European Water Framework Directive (WFD) 2013/39/EC and into the risk assessment of the European biocide regulation 528/2012.

Irgarol is persistent in aquatic ecosystems, toxic to algae and underwater plants and toxic for reproduction to water snails.


Sampling area

Sampling period

2006 - 2012