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• To test leaching during construction phase, a tank test for fresh concrete was developed. • The new test allows a more accurate assessment of the environmental compatibility for relevant applications. • Ba, Cr, Cu, V release was higher at young age. • Pb release was higher from pre-stored, hardened cementitious materials. Investigations concerning the release of potentially harmful substances are carried out on hardened concrete only and just in a few countries (e. g. Netherlands and Germany). However, in some applications, cementitious material can be exposed to water in a fresh state during the construction phase. Therefore, a tank test for fresh concrete has been developed. In contrast to common leaching tests, e. g. the European dynamic surface leaching test (DSLT, CEN/TS 16637–2) , water is applied on the fresh concrete surface rather than on a hardened, monolithic specimen. This paper summarizes the results of several research projects on this topic conducted during the last 20 years. For the parameters Ba, Cr, Cu, Pb and V, the leaching of fresh cementitious materials (concrete and cement grouts) including the subsequent leaching of the hardening materials are compared with DSLT results. For Ba, Cr, Cu, V, the release of fresh materials is significantly higher than that of hardened materials, which can be explained by the decreasing diffusion coefficient with progressing hydration. However, for Pb, the leaching of hardened materials is higher. [ABSTRACT FROM AUTHOR]