This paper examines how investigations played a part in ongoing learning processes at a Scandinavian refinery. Data regarding the roles of investigations was collected during six months of observations at the refinery and interviews with 70 employees. We focus on two investigated incidents, the rupture of a blowdown pipe from a steam drum and an incident that could have led to the injury of mooring operators during the mooring of an oil tanker. We found that investigations were used as part of efforts to learn from incidents at the refinery, but by far from all the interviewed employees. Investigations were described as having several roles. They generated new knowledge about the causes of incidents and confirmed existing knowledge regarding the dangers of corrosion for plant integrity and the importance of following mooring procedures. However, they also suggested measures that were not considered economically feasible or well suited for the refinery. In addition, investigations contributed to learning regarding issues that were not addressed directly in suggested measures, because findings were also applicable to other safety issues at the refinery. In light of these roles, we suggest that investigation groups should ensure closer cooperation with investigated units when developing measures, and work to ensure that investigation reports are used systematically as a learning tool among employees. This may increase the integration of investigation findings in important safety improvement initiatives and thereby the potential for learning from incidents. (C) 2014 Elsevier Ltd. All rights reserved.