Operational precautions for chemical tankers are vitally important in reducing the potential threat to shipboard crew by products carried. This paper enhances the international Safety Management (ISM) code in compliance with Occupational Health and Safety Management Systems (OHSAS 18001:2007) requirements in respect to operational constraints related to chemical tankers. As research methodology, Fuzzy Axiomatic Design (FAD) and Analytic Hierarchy Process (AHP) are referred to redesign the extended ISM code procedure, which identifies key points for occupational accident prevention on board chemical tankers. To illustrate the expected benefits of an extended ISM code procedure, the principle root causes of chemical tanker explosion are also discussed. In particular, the main results of the case study highlight the urgent need to ensure the competency of shipboard personnel and their familiarization with the characteristics of chemical cargos under differing circumstances. The outcomes set out in this paper contribute to regulatory compliance and to the management of occupational health and safety requirements on board chemical tankers. (C) 2009 Elsevier Ltd. All rights reserved.