This paper brings into focus simple sustainable development indicators to be used in the planning of the petrochemical industry. The indicators cover the three aspects of sustainability-environmental, economic and safety. The indicators serve as tools that can guide companies in assessing their performance in decision-making and planning for the future. These simple indicators of sustainable development are especially helpful in planning large projects or during the earliest stages of planning when most detailed process information is still lacking. These sustainability indicators were used as objectives for a mixed-integer optimisation model to plan the development of a typical petrochemical industry, and were found to be very useful in identifying a balanced petrochemical network. A simple Monte Carlo simulation showed that the model is able to accommodate variations in prices and demand. (C) 2009 Elsevier Ltd. All rights reserved.