On request of the Province of Overijssel the National Institute of Public Health and Environmental Protection (RIVM) carried out an investigation to: 1. A test method for industrial waste materials which should be accepted at a dumping site and taking into account the influences of the percolate that has been formed already by domestic waste (co-disposal). 2. An acceptation procedure on the basis of a short test method. 3. A list of components to be tested in this procedure. 4. A list of concentration criterions in terms of leaching and composition of the waste material. The RIVM started with a survey on waste materials which have been frequently offered for dumping. In this study use was made of the Standard Leaching Test (SLT). As leaching agent synthetic rainwater (SRW) was used in order to simulate a mono-disposal of industrial waste and synthetic dumping site percolation water (SPW) was applied with a view to the behaviour of industrial wastes in co-disposal with domestic waste. Fourteen industrial wastes were leached out. The percolates were analyzed on the elements As, Cd, Cr, Cu, Hg, Pb, and Sb.