This paper proposes a framework for the detection of information leaks in workflow descriptions based on static information flow analysis. Despite the correct deployment of access control mechanisms, certain information leaks can persist, thereby undermining the compliance of workflows to policies. The framework put forward in this paper identifies leaks induced by the structure of the workflow. It consists of an adequate meta-model for workflow representation based on Petri nets and corresponding components for the transformation and analysis. A case study illustrates the application of the framework on a concrete workflow in BPEL notation.