Dr Jens Schumacher is an application engineer at FRAGOL and an expert in the regulatory classification of heat transfer fluids. The chemist explains in detail why the use of the aromatic hydrocarbon dibenzyltoluene (DBT), the basis of the well-known heat transfer oil MARLOTHERM® SH, should now urgently be stopped. Last but not least, the legislature requires a substitution test for health-endangering CMR substances such as DBT.