Mineral wool products are man-made vitreous fibres that are used as thermal and acoustic insulation materials and as substrates for horticulture. Mineral wool waste is generated from demolition activities by the building and construction industry. Unfavourable mechanical properties, such as low compressibility, elastic behaviour, high volume and low bulk density, cause problems in landfills when mineral wool waste is disposed of. Mineral wool waste with a certain content of carcinogenic fibres is classified as hazardous waste type 31437 g “Asbestos Waste, Asbestos Dust” in Austria, since some characteristics of such fibres are similar to those of asbestos fibres. An exception is those mineral wool materials that have been tested to be noncarcinogenic due to their characteristics of biological solubility or geometrical dimension. Such noncarcinogenic mineral wool waste is classified as non-hazard-ous waste type 31416 “Mineral fibres”. Generally, it can be assumed that most of the industrial producers of mineral wool in the EU have not been producing carcinogenic material since 1998; however, carcinogenic mineral wool material has not yet been banned in Austria. Therefore, a segregation between so-called “old” and “new” mineral wool material is not necessarily possible. The medical aspects of mineral wool products are still controversial. The International Agency for Research on Cancer (IARC) evaluated mineral wool (glass wool and rock wool) as “possibly carcinogen-ic” in 1988 but revised this evaluation to “inadequate evidence in humans for the carcinogenicity” in 2002. Fibrous dusts that reach the alveolar region of the lungs undergo a congruent or incongruent chemical dissolution process. Alveolar macro-phages ingest the intruded fibres and fulfil anti-infection and clearance functions. Biosolubility is a key property of this process. The recycling of mineral wool waste has not yet been performed in Austria due to economic inefficiency, technical problems and suspected health issues. However, some recycling and processing options already exist; other options are investigated in the project RecyMin, which compares different concepts with respect to environmental and economic criteria.