The paper contributes to debates on dark phases of regional industry path development processes. We focus on the role of industry legitimacy and study legitimacy spillovers from contextual structures in the case of the biogas industry in Scania, Sweden. Previously presented as a success case, we show how legitimacy spillovers from various contextual structures influenced the path development process, in both the emergence and acceleration phases, and in the recent decline period. The analysis highlights how previously accumulated resources in the form of knowledge, finance and market were insufficient to prevent industry decline when it suffered a loss of legitimacy.