Considerable resources are being devoted to tracking an exponential increase in the number of voluntary ethical sourcing initiatives which promote objectives reflecting principles in the Universal Declaration of Human Rights, the ILO Declaration on Fundamental Principles and Rights at Work, or related practices. So far, the emphasis has been more on which principles are endorsed and on arrangements for verification of application. This includes statements on worker health and safety. Most of these statements, however, remain general and refer to codes of practice in which engineered or `scientific' monitoring systems are used to promote and verify a safe product more than a healthy and safe work environment. Few statements address how such standards are governed, whether they extend beyond the remit of the factory floor, or how they address workers' own short and long-term health concerns. By contrast, comparatively less emphasis is placed on understanding the management methods, priorities and definitions such rights-based initiatives use to give effect to their labor policy objectives, or to ascertain whether their objectives are attainable in practice. Even less is known about the extent to which the scope of the application is being enlarged to include appropriate and relevant issues and stakeholders. This includes worker health and well-being issues and their relevant stakeholders, including government bodies and institutions, and the extent to which they are fulfilling their own remit in this application. Finally, knowledge is especially scant about the way in which actors, particularly in developing countries, prioritize, implement and govern these worker health standards and how relevant in context or beneficial they are to worker welfare. The overarching aim of this thesis, therefore, is to consider how both the methods and the purpose of ethical sourcing can lead toward establishing an ethic with which to apply rights-based frameworks. Qualitative research was carried out to describe and identify the opportunities and challenges implicit in promoting a right to health and well-being for workers in transnational supply chains, particularly within the Kenyan floriculture supply network. The objectives of the research reflect on: a) definitions of ethics, human rights, health and well-being and the way they are being described in current ethical sourcing trends; b) the benefits, tensions and ambiguities in implementing worker health standards; and c) how and what worker health standards should be governed. The research primarily focused on a case study approach (Kenyan floriculture) to explore the scope and involvement of stakeholders and the ways in which worker health were interpreted and prioritized. Concepts emerged during the process of the research and were analyzed using `grounded theory' (Glaser & Strauss 1967) as a means to explore and explain key issues that contribute to the dilemmas and opportunities of promoting ethical sourcing initiatives, particularly for worker health. These categories of findings were then organized to ascertain the benefits, tensions and ambiguities in promoting an ethic for applying human rights standards -- an ethic that upholds a dynamic, comprehensive and democratic process in promoting worker health and welfare. These data were then used to develop an analytical framework in terms of viewing the scope and governance of worker health rights. Finally, key recommendations are made on the opportunities and challenges of ethical sourcing approaches in promoting worker health and welfare goals. This thesis argues that worker health and well-being standards are often interpreted and promoted according to the capacities and priorities of those who are managing them. In the case study, it was found that larger export floriculture producers are able to provide a range of health benefits and services to their workers unlike their smaller scale cohorts. Other case study findings revealed that key worker health targets involved addressing customer health concerns over worker wellness issues. These findings support the idea that ethical standards are often interpreted and applied according to consumer priorities and values over producer driven ones and only target those workers directly linked to transnational enterprise networks. Some policies intended to protect workers were rendered discriminatory in practice. Governance, participation and responsibility in giving effect to worker health and well-being standards remained predominantly with the business sector; government and civil society were minimally engaged or responsible. Thus, this study's research findings concurred with the evolving notion that worker health and well-being is not sufficiently governed hen applying transnational ethical standards without a local context of support (via laws, infrastructure and civil society) and, therefore, at present will not achieve a widespread realization of rights.