Three organosilicon compounds, often referred to by their abbreviations D4, D5, and D6, are considered to exhibit a slow degradability in the environment. In addition, they accumulate in organisms and exhibit toxic effects. As a result, they have been on the SVHC list as PBT/vPvB substances for some time now. In addition, a general ban on the sale of these three substances is in effect, although exceptions are permitted for certain applications.