Analyses of social and environmental management in transnational product chains focus often upstream on suppliers in socially and institutionally vulnerable countries and these suppliers' hazardous processes. Furthermore focus is on transnational companies' responsibility when they source from such suppliers. On the contrary, not much focus has been on transnational companies' downstream export of hazardous products to vulnerable countries and the product use in those countries. The article uses pesticides as case of hazardous products and identifies mechanisms in the downstream social and environmental management of a Danish pesticide company in vulnerable countries and especially in Brazil. The identified mechanisms are: the transnational company's on-going interpretation of the regulatory and ethical obligations for development and use of its hazardous products in vulnerable countries, path dependency and path creation in the business strategy, geographical and organisational coverage of the management systems and practices, the willingness of the company to address social and institutional vulnerability in use countries, and the roles of users and other actors in development and facilitation of more sustainable practices. The mechanisms are discussed with reference to other analyses. In the conclusion the mechanisms are presented as themes in future research and civil society organisations' activities and as guidance in businesses' development and assessment of more sustainable management practices. The benefits of transnational research cooperation for this type of research are also discussed.