Critically assessing the role and influence of trade unions on occupational health and safety (OHS), and tracing their contribution to OHS discourse, is here examined through the lens of history in Britain positioned relative to international experience. The idea of trade union neglect of OHS is challenged through study of the historic role of trade unions and the more recent experience (since the 1970s) of unions’ growing interest in OHS whilst simultaneously experiencing a sharp decline in membership and the adverse impact of this disempowerment on OHS standards. Acknowledging the politics of gender shows British unions neglected occupational health and embodiment issues that impacted upon women as workers. Robust and compelling evidence from the mid-twentieth century - that unions were a powerful countervailing force to workplace dangers, as key sentinels shielding workers’ bodies - is followed by evidence of increasing occupational illnesses in the period of union decline and precarious work from c. 1980. The article urges more critical reflection on trade unions as actors and as a voice in the OHS discourse.