In the European member states, there are strict laws in force on biocides. The so-called biocidal products regulation (BPR, Regulation (EU) 528/2012) concerns the use of biocides as protection against harmful organisms, such as pests or bacteria and more specifically on the effect of the active ingredients in the biocide. The directive includes among other things that not all salts may be used for making biocides (chlorine). So, which type of salt is suitable for biocides? Here is an overview.