Many studies have been completed on the benefits that can be achieved through the use of the lean production philosophy to meet the challenges of sustainable development. These benefits include reduced waste, lead time, inventory and improved efficiency. Due to the rising recognition of global climate change, this paper aims to identify the contribution of the lean production philosophy towards environmental sustainability in precast concrete factories, using CO2 emissions as the indicator. This study adopts a weighted factor model comprising 17 precasters in the Singapore precast concrete industry. Two stages in the production cycle are investigated using the weighted factor model, which are site layout management and delivery management. The results indicate that there are many non-value adding activities in the precast concrete production process that contribute to an increase in the level of carbon emissions. Large storage area, large quantity supply base, lack of JIT sourcing with the suppliers and lean workforce seem to be the most important non-value adding activities in site layout management and delivery management. The analysis provides good practice guidance and can be used as a checklist for precasters to identify the non-value adding activities in the precast concrete production process to achieve low-carbon production. The results will also be useful for regulatory agencies to provide recommendations for the precast concrete industry to reduce carbon emissions.