This paper analyses the user safety of a playground built out of reused blades from a dismantled wind turbine. Located in Rotterdam and designed by the Netherlands architecture firm Superuse Studios, the playground, called “Wikado”, represents an example of the circular economy applied to the built environment. With reused materials, Wikado represents a saving in resources and energy, when compared to a standard playground built with primary materials. Furthermore, the playground creates a unique design experience for its users, who can still recognise the original rotor blades following their transformation into slides, platforms, and tunnels. However, the safety of the playground could be questioned. This paper will analyse the materials and products used in the playground and their condition some years after opening. The analysis focuses on the risks of human health during the use of the playground. It considers the shape and the sharpness of the rotor blades, its components such as glass fibres and epoxy resin. As a result of the analysis, two risk analysis conceptual models help to assess the health concerns regarding the contact with the materials, and some yellow drops leaching from the rotor blades. This analysis informs the contemporary debate concerning the reuse of materials, and more generically, the circular economy applied to the built environment: whether it is recommended and safe to reuse materials for a different function from that which they were originally designed. This paper will explain that in the analysed case study, it can be safe to reuse materials for a different function, but only with the appropriate precautions.