Process safety and risk management systems are implemented to reduce injuries and process incidents. The effectiveness of these systems is dependent on the company's implementation and support for operational discipline (OD)-related programs to ensure that the process safety management system requirements are followed day-to-day at all levels of the organization. However, OD-program-related problems continue to contribute to process incidents, including loss of containment (LOC) incidents, especially since they may not be formally addressed during incident investigations. This article provides a brief historical overview of major LOC incidents, describes how poor OD increases process safety risk and can contribute to LOC incidents, and provides an incident investigation tool to help monitor and improve OD characteristics. (C) 2011 American Institute of Chemical Engineers Process Saf Prog 30: 216-220, 2011