Fire potention has several aspects that must be considered when building an LPG (Liquified Petroleum Gas) tank so it can be used according to its function. The most important aspect that must be considered is protection against fire and explosion hazard. The LPG (Liquified Petroleum Gas) oil tank which is reviewed in this final project is Spherical Tank C-20-01-B located at PT.Pertamina Persero Balikpapan. The purpose of this research was to assess the risk of explosion and fire in the work maintenance of lpg (liquified petroleum gas) tank capacity of 8.000.000 liters. Research data obtained from the results of form based interviews with a scale of 1 to 4, and direct observation to the field and based on secondary data in the form of documents such as drawings, unit price workers, methods of work. Result of this research got two factors causing fire and explosion at LPG tank that is internal an external factor. The internal factor is work that has the highest risk level is painting work with PFP material epoxy intumescent equal to 12 high risk ratings, mechanical colomn preparation work equal to 9 medium risk ratings, dismantling colomn bordes pole work 12 high risk ratings. While the external factor is BLEVE have value equal to 12 high risk rating, vapor cloud explosion has a value of 12 high risk ratings and leakage on the tank has a value of high risk ratings.