Consequence assessment is an integral part of risk assessment process. There are many types of consequences loss due to pipeline failure such as assets loss, environmental loss, production loss and human health and safety (HSE) loss. Yet, some of these factors are often neglected in environmental loss assessment such as agricultural, demographic, industrial and local factors. In real life problem solving, the factors of environmental consequence are not assessed precisely due to unquantifiable, deficient and lack of knowledge on the real on-site parameters. These limitations lead to the use of fuzzy-based approaches in environmental consequence assessment using on-site parameters as the main focused on this paper. Even though the basic model can be comparable to other established model, a lot of customization needs to be carried out network-wise, based on the carried products by the pipeline, locally applicable regulations and geographical surroundings. Knowledge of local conditions, past history and experience of similar incidents, are required to be considered and incorporated to provide a realistic picture of environmental consequence model. The damage area of the incident is calculated using ALOHA software by considering the details of the site such as atmospheric and topography condition. Finally, the proposed methodology is applied to a case study on high consequences areas of buried gas pipeline site in Malaysia to generate the environmental consequences index represented in each selected sites. The result can be utilized to determine the overall consequences loss using appropriate simulation analysis.