High levels of complexity for capital projects and turnarounds in the oil and gas industries have historically led to some of the highest project losses. The application of traditional risk-models and management principles has proven insufficient to prevent a high rate failure in this sector. Empirical evidence collected for various oil and gas related projects and plant turnarounds suggests risk categories, which, if left insufficiently managed, can lead to severely negative project impacts. This paper presents the most significant risks identified by project and turnaround teams in the oil and gas sector, and presents tools and techniques to improve the effectiveness of risk management.