This paper describes a case study in which Quantitative Risk Assessment (QRA) was used as the background for lay-out modifications to improve the reliability, and thus the productivity, of a batch plant for distilling the production residues of a photo initiator for ecological paints. QRA identified the plant's critical features. Its reliability was assessed in the light of the literature data coupled with its reported anomaly history. Theoretical improvements in reliability were put into effect through unscheduled maintenance operations. Redundancies, for example, were introduced in the solvent tank level control system and the solvent line valves were replaced with a more reliable model. (C) 2003 Elsevier Ltd. All fights reserved.