The Netherlands' State Secretary for Infrastructure and Water Management has proposed a definitive ban on the use of steel slag — a byproduct of steel production widely used as a cheap construction material in road-building — unless its safety for human health and the environment can be demonstrated. The proposed rules are expected to take effect next year, replacing a temporary ban introduced in July 2025 and extended through January 2026, and would cover both land-based and water-based applications. The move follows ongoing concerns that the material leaches pollutants when wet, though the State Secretary acknowledged steel slag remains an important alternative resource amid raw material shortages, and said a final decision will be made by the end of the year, informed by research from the RIVM (the Dutch National Institute for Public Health and the Environment).