Crumb rubber from recycled tires is widely used in synthetic sports pitches despite environmental and health concerns. The study presents a case study that draws, first, on existing relevant scientific literature, though it does not constitute a systematic review. Second, it identifies the chemical composition of crumb rubber and examines its environmental and public health effects. These two strands inform the subsequent policy and regulatory analysis of the limited number of policy documents from Great Britain, along with a consultancy report, addressing crumb rubber and third-generation (3G) pitches. Research shows that crumb microplastics are present and, according to the European Union, they produce a range of negative (eco)toxic and physical effects on living organisms, and cannot be contained effectively. Crumb rubber, therefore, cannot be used sustainably within Europe’s circular economy and zero-plastic-pollution policies. Available policy alternatives were briefly considered in relation to risk assessments, life-cycle analyses, industry economic interests, and governmental and sporting-body sustainability policies. Finally, an analysis was provided on how government bodies, local authorities, and sports organizations have started to interpret and implement the consultancy report. Great Britain’s policies appear to be partly based on flawed, incomplete, and selective assessments of evidence, with asymmetrical risk assessments. Nevertheless, they closely align with and reflect many of the policies and practices adopted by international sports bodies concerning 3G pitch materials. Questions remain regarding how precautionary public health and sustainability policies for crumb rubber derived from used tires and other sources can be improved.