Ferrous slag and the environment
Sustainable business practices are becoming increasingly important. Businesses and organisations that conserve natural resources, ensure a reliable supply of raw materials, promote circular production and drive forward climate protection will be successful in the future from both an economic and an ecological perspective. The Circularity Gap Report, for example, demonstrates that action is needed: the world is currently only 8% circular. The European Union is therefore calling on its member states, among other things, to improve resource efficiency. In this context, the use of by-products and secondary raw materials is becoming increasingly important in Europe. Ferrous slag has been making a significant contribution to this for decades.
Safe for people and the environment
The proper use of ferrous slag in building materials and fertilisers causes no harm to water, soil, plants or people. The levels of environmentally relevant components in ferrous slag are comparable to those found in natural rock, and the release of these components into the environment is very low. Numerous studies confirm that the use of fertilisers containing slag or the use of (road) construction materials containing ferrous slag do not lead to any negative environmental impacts. Furthermore, as by-products, ferrous slag already contributes to the circular economy in its ‘first life’ – unlike, for example, recycled products.
Furthermore, ferrous slag is a substitute for natural rock! In total, this amounted to over 1.2 billion tonnes of rock saved in the European Union and the UK between 2000 and 2024 alone – a significant contribution to resource conservation.
Another environmental benefit: using granulated blast furnace slag instead of Portland cement clinker in cement significantly reduces the carbon footprint. Between 2000 and 2024 alone, this measure prevented the emission of over 320 million tonnes of this climate-damaging gas in the European Union and the United Kingdom.
Ferrous slag and REACH
Ferrous slags were successfully registered with the European Chemicals Agency (ECHA) in 2010 as UVCB substances („Unknown or Variable Composition, Complex Reaction Products or Biological Materials“) in accordance with the REACH Regulation [LINK]. The registration was carried out through the REACH Ferrous Slag Consortium (RFSC), managed by the FEhS-Institute as consortium manager.
The RFSC brings together 155 steel and slag-producing companies as well as processing companies, representing approximately 97% of EU-27 crude steel production.
Over the past two decades, the RFSC has carried out extensive toxicological and ecotoxicological studies on ferrous slags in accordance with the requirements of Regulation (EC) No 1907/2006 (REACH). These studies cover human health-related endpoints, including acute toxicity via oral, dermal and inhalation exposure routes, as well as potential environmental effects on plants and soil organisms.
The results demonstrate that ferrous slags do not exhibit hazardous properties under foreseeable conditions of use. Accordingly, they are classified as non-hazardous under Regulation (EC) No 1272/2008 (CLP).
Recent regulatory developments at national level have led to further discussions on the assessment of ferrous slags under REACH. In particular, a provisional measure introduced by the Netherlands under Article 129 REACH has triggered additional activities at EU level. In this context, further studies on human health and environmental aspects have been initiated. These activities contribute to the continuous evaluation of ferrous slags within the established regulatory framework.
The registered ferrous slags were grouped into five main slag families using a read-across approach (see Table 1).
