Based on a case study of an assembly plant in a large US corporation, this paper reports on cultural and environmental influences on the form and process of workplace alcohol policy. Utilizing both ethnographic and survey methods, research findings indicate that although alcohol policies are in place, management and union leaders are unclear about their source and content, and the general employee population perceives alcohol availability and on-job drinking as poorly controlled. In grounded theory fashion, two conceptual themes are employed for organizing empirical explanations of the weakened policy and under-controlled drinking. These are: (1) the dual alcohol policy dilemma, and (2) the union-management debate over authority to discipline. The ambivalent nature of alcohol policy and organizational mechanisms involved in its implementation become risk factors for developing workplace-related alcohol problems.